Yes thought about it, but decided not to. I've already spent a lot more time and money than I intended to (while-I-am-at-it-itis is very hard to shake off!). The car hasn't suffered too badly over the last 40 years given that it appears to have had very little care and attention for a lot of that time and it will now be cossetted in a garage and probably won't venture out in the rain too often. I think the main thing is to try and keep the water out of the birdcage in the first place.
John