Thanks for the reassurance - The key seems to be the impedance, the dimesions of injector are the same - the '155' part signifies that. They are 4 nozzle and other than that I don't know how else they could vary. I guess in a lot of ways internally but info is scare on that level.
The only negative would be the colour I guess!
vs
Actually - just noticed the position for the retaining clip is in a different place. but I don't think the retaining clips are used with the adaptors?