no liability accepted for the following advise :-
tidy up his land yourself carefully rearrange the caravan scrap to a less offensive position conceal with planting put a fence/hedge up to include his land in yours.
treat the abandoned land as your own wait 12 years congratulations you now have a bigger country estate.
edit 10 not 12
“Positive Prescription provides that where someone has possessed land “openly, peaceably and without judicial interruption (a court action which challenges the possession in question)” on the strength of a valid recorded title covering the land in question for 10 years they will obtain a good title to it. Such possession can usually be proven by the provision of affidavits (sworn statements by affected parties)”