Thanks for all the input and advice from everyone; I love to hear people’s opinions, that is the wonder of this and similar sites.
I have toured many tens of thousands of miles by motorcycle and loved every minute but for a trip with no end date I have decided the Mog and small motor bike option is the one for me. I hope to set off when the time is right, but the date depends on selling a house etc. I have a house which is rented and has been by the same family for 4 years without issue, they look like they are staying put with 3 small children in local schools etc. My sister manages it for me along with her own properties as I work away a lot (currently in the stans) I have done 2 round the world trips before as a hitch hiker, first setting off in 1980 which lasted about 11 months and again for 2 years in 89-90. At that time I used hostels and camping, as well as renting while based in Aus for a while.
I understand the comments which say an objective is important, and I agree, if an end to the adventure is factored in.
My objective would be to live life, and feel free, without and end date or goal. I can’t imagine a single person on this site who has not dreamed of the opportunity to just travel. To set an objective is to set a limit or an end.
I hope to have a panic fund of 5 to 10k for emergencies. My rout would get me to Asia as quickly as possible, via whatever rout is the best at the time. I would factor in the ‘launch’ costs so would only start living on the rent money when I got to Asia.
So what do you think guys..... Am I on the right lines or raving bloody mad..... Cos I’m dammed if I know either way.

Actually, I've already done this quite a few times with mixed results. At the moment I've concluded it's not what I'm after, and as a result I'm not looking for more long trips, with or without objectives or limits. I don't think that this is uncommon.

The thing is, most folks vote with their feet. In other words, they talk about how much they'd enjoy life without plans or obligations, but in actual fact they accumulate responsibilities rather rapidly because there are real rewards to be had in commitment over time, in becoming a part of families, in embedding in communities, and in orienting toward goals.

It's convenient to complain and say "If I only had the money, I'd throw it all aside and take the endless motorcycle (or Unimog) journey," but the reasons that most people never actually accomplish this are for real, and worth considering realistically. It's very often not about lacking the funding: most people around here spend more per year supporting their giant televisions, stylish clothes and humongous American cars than I've spent on yearlong trips throughout the world no matter how profligate.

Whether this applies to you specifically is an open question. I'm just pointing out that I don't think your generalization is true.

Your central question, which I understand to be whether your budget will suffice, has been answered by a few posters already, and I'm sure others will chime in. It sounds like maybe you're looking for something else; what is it? "Am I crazy?" doesn't really narrow it down.

As always, ignore any or all of the above if it's unhelpful or doesn't apply.

Mark

Be aware that £500 per month in Europe goes nowhere even with free accommodation and that some people become travel weary after about a year.

If you rent your house 100% occupancy is hard to achieve and also you will have to give tenants a contract which means you wont always be able to return at a moments notice.

Other than that just go for it - better on a bike IMHO