Alex
To prepare my car for the SVA, I used a pair of Fiesta headlights from the scrap yard. They were nearly new, in good condition and complied with the SVA regs for marking etc. They included a sidelight. Of course, they were not the correct shape, but I was short of time prior to the SVA test and these were easily available.
Post SVA, I picked up a couple of new, boxed headlamps from one of the kit car shows. They were advertised as suitable for GT40's, but as I am not at home now, I can't remember the details. They are the correct size, with sidelight and markings, so still comply with the rules. They were a tight fit but look good. I can't guarentee their originality though.
Regards
Dave