FlyingGoat,
Public Liability insurance is generally quite cheap, so you should be able to get coverage of a few million for not too much more money...
I would also definitely say that £250k is a bit laughable for the reasons chrisbl pointed out... its not just the damaged parts themselves, but all the consequential costs too (e.g. legal, repair man-hours, inspections etc.).... and god help you if you manage to run someone over or kill them and you've only got £250k cover !
However, if its just a case of wanting to use your car an occasional few times a year for very short periods of time airside, then a friendly insurance broker might help get it worked into an existing car policy ?
Last edited by mixture; 29th Oct 2014 at 10:39.