This is where your handle-less gate valve is.

It sounds buggered, it certainly needs a handle.

I fergot to say, cause it was dinner time, that if you're lucky you may be
able to work it with grips on the stem of where the wheel useter be.

Try to grip the shaft; you can also try to unscrew the bigger nut at the
bottom to ease the shaft a bit. this may start to weep a bit, just
retighten it after you've got the valve open.

Aand of course, it's the cold taps you open. I fitted a drain cock at the
lowet point in the cold supply to your cylinder, if you're lucky you may
have one, which will cause less spillage when you replace the gate valve.

And when you replace it, consider doing it with a full bore lever operated
ball valve

http://www.screwfix.com/app/sfd/cat/...81454&id=21289

(you can also get them in yellow!)

mike