Yup - this is the problem I've had - everything starts at 8mm. And
I've looked all over...

displacement-activity

Wandering around the wotsit produces a supplier in China who claim:

"Capillary copper solder fitting are manufactured in accordance with
EN1254-1.
Size availability: 6mm -67mm , suitable for connecting copper tubes in
accordance with EN1057. "

see: http://www.double-winners.com/Stop_End(9301).htm

They have an email address on their site if you want to ask about UK
stockists, postage etc

Any use?

/displacement-activity
--
Robin
PM may be sent to rbw0{at}hotmail{dot}com