Sir John,
hope you got it right, without getting ripped off...........
I had the same troubles recently, after 3 visits to different garages nobody could pinpoint where it was leaking from.
I came here and found the o-ring page and did that job - still leaked.
Passed a Lexus Stealer, and they said it was the gearbox. This seemed odd as i was buying a tub of p/s fluid each week.
Sick of them all, i took it home and had a look myself.
The problem the garages had come across was that the oil was everywhere. I found it to be the figure of 8 pipe (open bonnet, look down behind radiator). well, the join with that pipe and the rubber hose
Took it off (headlight out and everything!) and saw that the pipe and its rubber neighbouring pipe were both in good condition and had no holes. Quickly figured that it was the 2 pincer clips holding them together. And didnt believe my luck
A £1.50 box of jubilee's later and the job was done.
The mess was b'cos it was leaking from that join and the fan was sucking it up and spitting it all out (sounds like them bloody women again!)
Job took a few hours (with brews!) and was chuffed when it no longer leaked.
Imagine if i'd paid Lexus for the gearbox leak??????????
I checked and there is no leak from anywhere anymore.
Gutted i wasted a fiver on the o-ring now