No fixed abode - Doc
How do people with no permanent address get insurance and what do they put on their V5, tax returns, etc.
(How do they get an updated V5 returned?)

I'm thinking of travellers, fair and circus performers, and the like.
No fixed abode - Flat in Fifth
I had to look at the date twice to check this wasn't April 1.

If you live outside normal society you can avoid lots of the downside to the niceties of life the rest of us have to pay for.....

In short a significant proportion don't bother.

No fixed abode - Armitage Shanks{P}
I think you can still collect your post from a post or sorting office (poste restante it used to be called). However it won't work as the address of where you live. There are agencies which, for a fee, will act as your address and forward stuff to you but a lot of them are in Central London so it will affect your car insurance if that is where you say you 'live'.
No fixed abode - T Lucas
Travelling people that i have dealt with have often had an address that is a relative that does not travel about anymore,a fixed caravan site for instance.Of course if you are just of 'no fixed abode'then you will probably not bother with the legal nicities.