Been using the standard late 620/800 APTC clutches for a few years now on the 620 with no problems.
My carp starts are definitely due to the bit that pulls in the lever, not what happens at the other end of the clutch line!
I got the last one off ebay for £80.......
This one looks the same though:
http://www.ebay.co.uk/itm/2609981316... 4.m1423.l2649