Try this:

http://www.ebay.co.uk/itm/22mm-Compr...3D141386607201

If you go for a stainless cylinder, hopefully you won't get any more leaking joints. Don't forget to weigh your old copper one in at the scrappy. You might have a pleasant surprise!

 

Yes, I might...and I also have quite a bit of brass and copper saved up too.

That rare fitting above is available over the counter at my local Jacksons Building Centre for £6.95 inc VAT.

 

Make sure all the brass and copper is separate. Don't leave any brass olives on the copper pipes as it makes it 'contaminated' and worth much less.

Putting 'Rare' on eBay, even if it isn't, allows you to ask far more than any item is worth, of course.

Incidentally, it may be you already have an anti-gravity valve in your system but it's stuck in the open position. I'd have a good look around before you buy a new one.

 

Defo not got one...I fitted it myself and didn't even know what one was.
There wasn't one with the older boiler, so I never put one in