Thanks for all the advice and ideas. Unfortunately, tractors are not cheap in France, I'm tempted though... Just had the French MOT done, loads of issues, one being a "gravely worn tyre" - bit of an exaggeration, but I've got to buy new tyres now!
Tractors are still fairly cheap in the UK as long as you are not expecting something perfect and do not go for a sought after "vintage" model, but it depends on what you consider to be cheap. I do not know what is required for import though. I bought one couple of years ago for £1800 I am slowly rebuilding (link), at that price a new set of tyres is half way to a tractor.