HELP with Surrey flange please. Need advice

[oogzy]

Could someone please help as i am in the throws of finishing my en suite and have hit a problem.
I purchased a Surrey flange a couple of months ago as i knew i would need one for my power shower installation. All pipework to and from my HW storage tank is 22mm so i assumed i had the correct flange. Today i decided to fit it and quickly realised the 1" male bsp thread was no way going to fit the outlet at the top of my tank. The outlet i have is 3/4".
I dont know why i have to have a non standard size... nothing seems to go to plan.
I have posted a picture here:
http://i194.photobucket.com/albums/z302/oogzy/DSC00107.jpg
I have found other Surrey flanges online with a 3/4 male tank connector but these only have 1/2" outlets to the system.
Would it be possible to use pipe adapters to size back up to the 22mm existing pipework, or will this cause a problem with bottlenecks etc? I could really do without shelling out over £200 on a new cylinder right now.
Advice much appreciated.

 

[gas4you]

Can't see why 15mm outlet would not be enough for a power shower.

Other option would be to fit an essex flange in the side at the top.

 

[chrishutt]

Are you sure the cylinder doesn't have a 1" female thread with a reducing bush (1" x ¾") or a 1" x 22mm fitting in it? It's hard to tell from the pic but it looks like it could be.

 

[oogzy]

Thanks for your quick replies.
I did wonder this myself as you can see the nut sits on top of a raised boss. As the raised bit is circular and no flat edges to get a wrench on, i assumed it must be part of the tank rather than a fitting. I need to cut the copper pipe in order to twist it out, and then im past the point of no return and have to get the job done. I just want to make sure i have all the bits i'll need.
Thanks again

 

[hi-spec plumbing heating]

don't matter if you use 15mm or 22mm outlet the inner copper tube that supplies the flange is only 15mm on both
just use a 22/15mm reducer to your existing pipework.

 

[oogzy]

Ahh yes i see what you mean - the one i have here has a 22mm tube, but this does 'funnel' down to 15mm at the top where it enters the brass main body.

 

[hi-spec plumbing heating]

so if your don't fit your tank get a 3/4 and use a 22/15 reducer on pipework.

 

[oogzy]

OK thanks for all your help.