I know exactly how you feel Lorna, and share in your frustration.
Both mine were smashed some time ago now, the off-side one totally, the near side one I managed to stick together with sellotape.
Brand new mine were going to cost £180 to replace !!!!!!!!!!! I managed to get a set off ebay for £46 but have been too scared to put them back on. I've probably been driving illegally (and carefully) for months now !
I've got my MOT this month, so will get my mechanic to put them on as he puts it through it's paces.
I'm serious considering getting some clear sticky backed plastic to put on BEFORE any further damage is caused.
The same little tinkers (yobs/neds/horrible horrible teenagers) make a regular habit of doing it to the whole street, AND the church windows at the bottom of the garden. I'm currently looking at 7 broken panes of glass that they will have to repair, and they weren't done all that long ago either. These windows are about 30' up as well !
The police patrol the area frequently but it doesn't seem to act as much of a deterrent although I did hear that they were starting to issues ASBOs to the parents rather than the children. We also have CCTV at both ends of the road for all the use that is.
I'd bring back the birch!
>:(