Thanks, I had already read that one but had seen reference to Ming's guide on a number of posts, although I couldn't locate it
I did it in the end yesterday afternoon. One bolt came undone easily with some WD40 and a wire brush, the other one at 90 degrees would not budge. However the metal bracket had almost come off the plastic housing so with a bit of pulling and twisting it came free leaving the bracket attached to the car!
The filter was very difficult to remove, had to resort to drilling a 10mm hole in the end of the plastic unit and hammering it out with an old SDS drill bit!
The filter was dated 2007, fitted to a 53 plate TD4 so definately overdue for replacement.
New, non genuine, filter was just as difficult to get back in, even after cleaning the housing completely and greasing it up.
There was a lot of crap in the sediment filter, so definately worth clearing this out on a regular basis.
Never mind, all done now!