Headlights causing a odd noise behind dash

[GT250]

finally got around to taking a look at the relays, seems it's not the culprit, but a possible dodgy connection nearby, which require removing the plastic cover that runs across the bulkhead.

what i did notice is the front fogs were switched on, and while they didn't work when i bought the car, they do work now (well one does) but it then causes the noise issue.

so for now i can leave the front fog lights off and happily use the headlights, until i can investigate further.

one question, i seem to recall a change in the MOT that requires all buttons on the dash to function correctly, so will this cause a problem come test time in April, or have i got that wrong and it won't be a problem?