Sure it's not just a 22mm? solder ring joints are more reliable than comap fittings for the average DIYer.
EDIT:
*notes the word slightly*
should be able to use a compression fitting
( da5id <YOUR SIG HERE>, Sun 2 Jun 2013, 9:19, 1 reply)

No, it's just a shade too wide for the joint I'm offering it. The nut won't fit.
Compression joints are the way forward for me. I'm too dangerous with a blowtorch. PTFE tape is my god.

Thank you for replying!
(Juan Quar is clinging to her front teeth on, Sun 2 Jun 2013, 9:54, closed)

If it's just the nut that's too tight on the pipe, but you can slip an olive over it and get it into the body of the fitting, it may be that the nut is deformed or badly cast.
(gordonjcp, Sun 2 Jun 2013, 12:15, closed)

No, the olive won't go on either.
You can see the slight difference in size if you compare them closely.
(Juan Quar is clinging to her front teeth on, Sun 2 Jun 2013, 16:56, closed)

if you can not get your nut to fit try dhaving it first. i found that it slips in easyer and a plus point is that hairs dont tangled and make your eyes water when you have finished

( fluffybunnykiller Is feasting on the clitoris of life, Sun 2 Jun 2013, 15:42, closed)

Thank you, I will try dhaving first
but I'll still have to pop to B&Q for a dhaver.
(Juan Quar is clinging to her front teeth on, Sun 2 Jun 2013, 17:00, closed)