New Clutch Slip

New clutch (full kit from dealer) fitted by the dealer back in June due to slipping. Started slipping intermittently again in August, took it back in to dealer and they disassembled and road tested but said there was no fault found.

Clutch has again started slipping intermittently but all clicked with me yesterday that it only slips after long runs in slow traffic (i.e when the car isnt getting cooled).

Anyone got any ideas before I face the blank expressions at the main dealer again?

(P.s, gearbox is new as of June 2015 as well).

Cheers.
 
just slave!

there have been a few masters sticking/not returning correctly causing clutch slip