Five weeks will give you a chance to see a lot, but not everything. Whether it is enough depends on what you want to see so post your proposed itinerary for comment.
As for car hire, I cannot specifically recommend any provider over another in the UK market, but avoid Green Motion like the plague.
“Great Britain” is a large island comprising England, Scotland and Wales. Ireland is a separate Island. The only rental company I know of to allow you to take their car from GB to Ireland and back is Hertz. However why pay to move someone else’s car on a ferry? it is easy enough to fly from various places in Great Britain to various places in Ireland and simply have a separate rental there.
Add EasyRent to the “do not use” list.
Thankyou. Can I just ask you is May a good time to travel over there
Thankyou for you advise I will certainly have a look at what you suggested
May is an excellent time of year, yes. Its my favourite in the countryside. Look out for bluebell woods earlier in the month. What are your interests? National parks, hills, coast, cities, art, churches, roman remains, castles, canals?
May is my favourite month for travelling in the UK and Ireland, too.
The next thing you need to do after deciding when you're com,ng over, is to start to build your itinerary. Ask yourself a few questions, such as where you feel specifically drawn to. Also consider where you'd like to start off, especially if you will be jet lagged. Would it be better to begin in a big city like London, or would you rather head off to some place more rural to rest up?
I usually recommend not renting a car automatically for the whole duration. As well as the advice about Ireland and Northern Ireland, there could be journeys you want to make that will be better done by train or air. London to York, Chester, Liverpool, Manchester or Edinburgh ar eexample where trains are usually better, while a trip from somewhere like Southampton or Bath to Scotland is one where a flight should be considered.
A mix and match approach is often more sensible than trying to drive to or from all four corners of Great Britain (ie England, Wales and Scotland). Cars are very good for mor eisolated regions, though.
I am not sure if you have been to UK before but driving in the UK is not the same as driving in Australia.
I see your population in Australia is around 25 million, our population is around 60 million, and we are a far smaller country.
So our major roads tend to be pretty packed with vehicles most of the time, and we get a lot of our goods delivered by lorry, so our motorways and major roads are often crowded with cars and lorries.
So driving anywhere in the UK is not the greatest of fun.
Even some of our larger "modern" cities are not a place for a car. For example, almost everyone would say having a car in London was a disadvantage rather than an advantage.
So you need to be aware of all these things if you are coming for a driving holiday in the UK.
As has been said, the countries of England, Wales and Scotland are on one piece of land and we all use the same money so it is possible to easily visit those three countries, maybe with a mixture of driving and some train travel.
Northern Ireland (capital Belfast) IS part of UK and uses the same money as us, but of course to get there you need to fly or get a ferry.
Ireland ("Southern Ireland") - capital Dublin - is a separate country from the UK and uses different money - the Euro. Again to get there you need to fly / get a ferry (unless driving from Northern Ireland of course).
As has been said, maybe if you want to got to Ireland (either part of it) then fly / ferry there and hire a car, though you need to tell them you are visiting both parts of the island.
I really think you need to plan this trip carefully, as if you are just going to drive round for 5 weeks then you are going to have to book a load of separate hotels / BBs which could get difficult and confusing.
While 5 weeks may sound a lot you are not going to see everything (even though the UK may look small from over there). I am over 60 years old and there are still many parts of the UK I have not seen.
So you probably need to think of your trip as 5 different 1-week trips and base yourself in five different areas, maybe a week in London, a week in Edinburgh, a week in South of England (Bath / Cotswolds area?) a week in Wales (North Wales / Snowdonia area?) and so on.
Then book a cottage or apartment in that area for that week, hire a car (not in London), and take day trips out visiting the areas nearby.
That will reduce the amount of moving from hotel / B&B, and also reduce the amount of driving all over the country.
I am sure you could get advice from other people who have done multiple-week driving holidays round the UK as any sort of advice and guidance will help your planning.
The first thing is to sort out where you are going.
Great Britain is the big island (clue is in the name), it comprises England, Scotland and Wales, add Northern Ireland and you have the UK, full name is the United Kingdom of Great Britain and Northern Ireland.
The Republic of Ireland is an independent country with a different currency, if you include it then you are visiting the British Isles (a geographical term).
Five weeks, a week in each country, would be minimum.
May includes two bank holidays - the first and last Mondays (6th and 27th for 2019), so those weekends tend to be busier. Also in England and Wales most schools have a half-term break around the later bank holiday - eg this year most schools are off now until the first Monday in June, so this week can be busy for families.
Otherwise, for ideas you may want to browse some of the trip reports from members for ideas that appeal (or not):
To assume that you must hire a car, without yet having an itinerary roughed out (cities, countryside or whatever) suggests you have not done any research into the excellent public transport system which exists here. Far different from what you may be used to at home. A car will not be the best option in many cases - getting from one city to another is easy by train (and usually faster and cheaper) . Only then hire a car if you want to visit rural areas without much public transport.