After giving adrian flux the details on the change the fella dissappeared to 'get the quote' and came back with bit of bad news.
Apparently, because I took the policy out on the modified ax they wanted an extra £150 (the ax with handling and engine breather mods was £400) which i thought was a bit unfair when performance-wise the ax ought to run rings round the vario and a higher agreed value
He then said ..... 'can you modify it in some way?'

Result!!!