After lots of chats and research - including contacting Matco - have gone with ATF instead of brake fluid. Advantages - doesn't eat paint or fibreglass (like brake fuild does) is kind to all the rings & seals and has a higher flash point than the Mil spec brake fluid - also cheaper and readily available. Downside - is not hydroscopic so any water entering the system will not disolve and will make its way to the lowest points - either the master cylinders or the slave cylinders on the wheels - and corrode the cylinders. Simply have to be careful to keep all water out and change the fluid at least annually ...........
After cutting all the lines loose and lowering them to try to get either the master cylinders or the reservior at the highest point - worked out it can't be done with the upward pipes attached the master cylinders. So followed the procedure anyway - got all the pipes as low as possible - and pumped fluid right back up to the reservior from each slave on the wheels. All looked OK until I pumped the brakes, and it was obvious that the the master cylinders were not filled - 4" of bubble appeared in each brake line.
A bit more research to go - but unless something else turns up, now that the lines are charged, I try the normal automotive bleeding technique from the reservior (pumping brakes and unlocking and locking the valve in the slave cylinders on the wheels). One advantage of the ATF is the low cost (and it doesn't damage anything if it spills) so I can keep trying without too many worries ........
