Well I know its been a while, but I have an update regarding auto box oil filter.
Car went for M.O.T. Thursday, and whilst there I asked about the auto box filter. It turns out that the filter is a gauze one, and it is deep inside the gearbox, which to do, means a total strip down. I was advised that another flush, and fresh oil, and it should be ok. The average change should be about every 40,000 miles. Which hopefully will out last the car, as I've only done about 8,000 in the last year.
And the other good news is that she passed with a couple of minor advisories.
A couple of brake pipes need cleaning up, and there is a slight blow on the join going into the rear silencer. So all in all, Thursday was a good day.