I wouldn't worry, as fredgroves has said I just might not fit their criteria for the moment. Btw I checked with Admiral too (who DTUK suggested) and they rejected it too. I guess the right approach with all modifications is to check with the insurer first and always call rather than use the chat function as I think that's how it ended up rejected by the underwriter in the first place. Interestingly I asked DL about a cold air intake and they said I would receive a refund of £40 so who knows what's happening!
Sorry for hijacking your thread boulton, I hope you have fun with your tuning box... not jealous at all!!