Lots of sound advice above

personally I wouldn't go with the fly/buy/drive option. It limits your preparation and what you can take.

It can be a lot more complicated than you probably think to buy and insure a vehicle in a country you don't live in.

One of the keys to vehicle reliability is history and familiarity with your vehicle. Everytime you buy a different vehicle your buying an unknown and taking a massive gamble, Instead I would buy or import a suitable vehicle in the UK and then spend some time getting to know it. Find a good reliable garage to work on it and cultivate a relationship, they may teach you a lot. I helped (hindered!)the garage I use prep my vehicles.I would say own the vehicle for a minimum of 12 months prior to leaving, preferably longer, even if it's a new one. Plenty of new cars have inbuilt faults! Even Toyotas! My Hilux had to have a new steering rack under warranty.

One thing to consider is most disastrous vehicle stopping mechanical problems take a while to develop, electronic ones can be sudden and unexpected

When considering the age and value of a vehicle, consider the carnet implications, you can save a lot on your carnet by buying an older vehicle and doing it up because the standard market value for carnet purposes will be lower. In places where you need a carnet I think you may find it tricky if the vehicle is from a different country to you, but I have no experience of this so others may know better.

There are extensive posts on here about the pro's and cons of new vs old vehicles so I won't go over them again. Read them, there are valid arguments for both sides.

Start with little trips, maybe as suggested eastern Europe, or morocco is a great place to explore. you may find this travelling lark isn't for you. A guy I know put everything into a RTW motorbike trip, and turned back at Italy!! If thats you, then fine, it's better to find out than not to even try and spend your life dreaming of what could have been. On that vein, don't let the dream and the planning become the event in itself, some people reach the ultimate extension of this and have a vehicle, and an elaborate plan, but never actually travel, you'll often see the vehicles on ebay!

with that in mind, don't burn your bridges. put your stuff into storage and rent the house out! apart from anything else if you decide you really like this travelling lark the rent may provide you with an income to carry on doing it!