Just finished a conversation with the garage.
Apparently, they put in 2 x 11 65 8509 323 and had to fit a different bracket - 11 65 7811 834.
Can't actually find these online, but they are also called "Pressure converters" and there seems to be similar threads talking about replacing these.
As it happens, I have also had to replace the glow plug controller and the vacuum hoses which are perished. All in all, an expensive trip!
Hope this helps and good luck. Apparently, this is a very fiddly job.