The exhaust sampling probe cap of my trusty BF90 has disintegrated resulting in hot exhaust gases melting a hole in the under-cover. I'm putting this down to age and a design limitation rather than being symptomatic of a problem elsewhere (everything else seems OK), but would welcome any comments. Having Googled it, I can find no reference to this as a spare part - can anyone recommend a likely online source? (I'm in the remote Scottish Highlands, so dependent on Internet purchase.)