Thanks for the information Donnie. This begs the question: is it a worn pump that makes the relay connection fail or is the pcb not up to the job in any case? One possible answer would be to know how many failed in the first year on a good pump.
The 230CE was made in 1990 and has done over 150k miles. Although the pump sounds fine at the moment, I will check the current (when hot) and also recheck the relay joint in a couple of weeks to see if it shows any signs of deteriorating.
My electronics experience tells me that 7A is unlikely to cause the solder joint to fail per se, however, it may possibly have 'crystallised' over time due to repeated heating and cooling. That being the case, it reinforces my original suggestion about routinely checking the condition of the relay pcb on older models.
By a strange coincidence, I once had this fault on a BMW E30 and it left me stranded in the snow at midnight; a bad experience I do not wish to repeat.
I'll drop by with any updates. Cheers.