Just back from taking my 205 GTI road rally car for its MoT so I thought I'd ask the tester.
The simple answer is that as long as (i) they go off when dip beam is selected, ii)they don't mask either the headlights on dip or main beam (by their location rather than light spread) and iii) any bracket they are mounted on is constructed in such a way to prevent injury to pedestrians (i.e. no sharp edges etc) then all will be well.
The only other regulations I know of are those published by the MSA in the blue book which limits maximum lens size to 222 mm diameter - but thats for competition purposes not road use!!
Sorry for the dissertation, hope this helps
Last edited by Arwyn Williams; 23/03/16 04:33 PM.