ORIGINAL: zcacogp
Martin,
You can buy some clear epoxy resin, by Araldite (not their regular stuff) - this sort of stuff:
http://www.ffx.co.uk/tools/product/Araicsyr%20Instant%20Clear%20Syringe%20Pack%20Araicsyr%205000399006053%2080805%20list
I have used this to good effect on holes very similar to yours in my lights; take the lights off, clean them very throughly with a toothbrush and warm soapy water, dry them, put a piece of tape over the front of the hole and fill the back of it with clear resin. When it has set, peel the tape off and you will struggle to spot where the hole ever was. (The resin has a very similar refractive index to the glass so is effectively invisible.)
I did this to one of my lights about 5 years ago and it's still as good as new.
Put some protectors over them to prevent it happening again. (I use helicopter tape and think it's excellent stuff although there seems to be a craze for much bigger, bulkier protectors these days.)
Oli.
ETA: Sorry, just seen that you have already bought the replacement lights! Never mind. Hope this post is of use to someone else.