Tip. Use methylated spirits to strip off the surface film: it just peels off if you leave it to react for a while.
edit Remove the headlamps from the bonnet before you use meths, it can damage paint if it is in contact for any length of time.
If only I'd known this yesterday - that film is really hard and takes some serious sanding. Still, I've only done one so far - I'll try meths on the other one.
Funny, I did (one of) mine yesteday too. I tried the meths but didn't know how long 'a while' was. Less than 20 minutes certainly isn't! Despite only 30% of the lens still being coated with the lacquer, it took around 3 hours to sand it off. I've got another light to do now this weekend and will try soaking for a few hours instead...
Annoyingly for me, despite getting the outside of the lens almost 100%, the inside is coated in grime. I'll need to open it up and clean that too
Lessons Learnt for me
Don't use sand paper at over 800 grit to start with - it needs to be a LOT coarser, especially with lacquer.
Don't bother trying to use an electric buffer - the shape of the lights make it near useless. If only she had a flatter bottom, damn woman!!