I have Secur-a-cat cat proofing too, I was lucky enough to win a standard kit (big enough for a 50ft x 50ft garden) in last years charity Xmas auction here on Purrs that the owner of Secur-a-cat, Roz, had very kindly donated but I believe the standard kit retails for around £300.
I put the system up myself with the help of my brother in law, neither of us are very good DIY-ers but it was simple enough if not time consuming - it took two days! Here's a few pics of the system in my garden:
http://www.purrsinourhearts.co.uk/index.php/topic,14221.msg244556.html#msg244556My boys have been going out for 6 months now, one of them in particular is amazingly athletic not to mention very persistant and clever! Not clever enough or athletic enough to 'beat' the cat proofing though, it has kept them both safely within my garden and I'm thrilled with it.
Roz couldn't have been more helpful, she always responded to my emails and queries about how to fit the sytem to my particular layout and fence type and was on the end of a phone if required. Can't recommend Secur-a-cat highly enough