380sel warm restart

[AF300E]

I have just done a full rebuild of the motor in a recently aquired 1992 380sel (euro spec, non-lambda).
All is well except that if the motor is at operating temp and i switch it off and leave for 30 mins or longer it becomes hard to re-start. When cold (if left for a few of hours or first start of the day) or if only switched off when hot and left for less that 15 mins, it starts first turn of the crank.

I have read about fuel accumulator symptoms and suspect it as a first but am wondering why it only affects the hot restart and not cold start.

Also, to test the accumulator i have removed the return line (out of the accumulator) and run the fuel pump and found that fuel runs out of the return line. I understand this to mean that the accumulator is faulty. Is this the case?