Hello RS3100 (is that your correct title) and Dickie813, Thanks for the replies and I am sorry I have not got back to you sooner but it has been raining quite heavily and to get at either of my OBD2 sockets, one on my car (Nissan Pulsar) and the other on my Fiat Ducato based motorhome of 2007 vintage, ones legs need to be out of the vehicles. This morning it is not raining so I now know that both plug in to my car and one plugs in with difficulty to my motorhome and the other (more expensive) does not plug into that vehicle at all. Maybe if I had a handle on it (as a French mechanic I saw doing it recently did) I might be able to get it to go in.
It was that French mechanic who caused me to think I needed one as he charged me €317 to replace my fuel filter, a job I could have done easily myself in ten minutes had I known it needed to be done. I could get one for £120 here and that is for the whole thing and £22 for just the cartridge. Saw me coming eh?
Just to answer your questions, yes I have opened both the lids and the wide side goes up in both cases with the little ridge underneath.
Actually, as a member of ADAC it strikes me, had I not thought the fault was something entirely different I should have probably got them to come and do it for free and just charge me wholesale for the part.
Harry