our cat snowball got pregnant to a feral - he broke in throught the catflap and after he'd pee'd up all my brand new kitchen units realised he was stuck in as flap was on 'in only' in an attempt to stop in season cat getting out. he then proceeded to smash all the mugs and rip curtains which obviously woke us up. when we tried to get him out of the house he was like devil-cat and we were kitted out in several layers of clothes, oven gloves and all the protective stuff we could find!
in a nutshell, there is NO way I could have caught him to get him to the vet and have his bits chopped (much as I'd love to)
Roxy, I think you are a star, you don't have to care for these cats and kittens but you do it because you are a nice person and they are lucky to have you!! in fact I think word is out in the feline world that your caravan is the best maternity unit in your local area ;0)