You can possibly try through an insurance on the European Continent if you have difficulty in the UK. When I picked up my export home delivery car in the UK I had it insured through an insurance broker in Germany because I also didn’t have an address in the UK. On the Continent you only have to give them an address through which you can be reached. You don’t have to actually live there. A co-operative dealer will suffice. I think Jessen was the name of the broker that I used and they had offices in Hamburg, but I can’t find them anymore by Googling.
Edit: I have found a telephone number that could be the broker by the name of Jessen that I used: +4938183922, in which case he would have moved his office in the meantime to another town. Anyway, even if it isn’t he may be able to put you on the right track.