Michael,
I got the CF pipes from the Netherlands, through a befriended boatbuilder. I heard the manufacturer does 'trade only'.
Matt Newland has the contact, maybe he can quote you.
I think Matt has started selling CF masts as an option. The great advantage of CF masts is weight and .... buoyancy. Through their reduced weight they increase the AVS (Angle of Vanishing Stability) i.e. that heeling angle from which the boat would fall down flat on the water with its mast instead of self-right itself.
Then, the hollow CF mast has greater net buoyancy which would prevent the boat from going 180 degrees turtle after a knockdown.
Not that capsizing should be a constant concern, already the standard BR and SR with their wooden masts are far more stable ande safer than any other peer size boat on the market, bur it can be noted that a CF masts adds further AVS.
CF mast costs: CF is a hot item, demand far outshining supply, since they started to build planes and naval vessels from it.
However, there may be a fairly cheap alternative for you, if you would consider a standard windsurfer mast on your Storm Petrel, they are comparatively inexpensive because they have become such a commodity. There will also be a Winsurfer Shop near where you live.
The trick for you would be to look for a very long and high carbon content windsurfer mast (not slimline profile, standard diameter!) with a high IMCS ( Rigidity Index; >= 32). If you shorten a long high IMCS mast, you get the strongest and stiffest possible (windsurfer) spar.
To fasten screws in 3 mm wall thickness is still absolutely fine, only I use the inside of the wooden plugs to give the main screws for the clamps even better grip.
For wall thicknesses below 3 mm, I heard they use a drop of epoxy resin on the thread of the screw to fasten it firmly.
Good luck.
C.