Thanks for your reply.
I have a third hard drive in a caddy with a rocker switch which I got sometime ago. I had a look on eBay last night and found identical caddies at about £16 each, so, yes, that would be the best option, especially as I could use a couple more hard drives and, it would save me mucking about with my soldering iron!! Although I don't think the circuit would be difficult, I recon about ten components, 3 resistors, 3 cap's, 2 diodes, 1 4017B, 1 4001B. All of which I already have. The only trouble with DIY electronics is that things never turnout as simple as you expect!!!
regards Bishka