Are you finding oil on the fork stanchion now? If it's no worse, a good clean before the test (lift up the dust cover on the top of the slider and give it a really thorough wipe under there too) should leave it clean enough not to attract unfavourable attention from the tester (I presume MoT time approaches?)
If it is leaving oil deposits on the stanchion then it's time to get the seal changed. Not too expensive, but I don't know of any dealers or mechanics around Melksham so you'd need to tap into someone's local knowledge for that.
