I have seen pushrod leak reparation with araldite. It must be cleaned very well though..

Double check it's not the banjo joint on the oil feed before you start ripping it to bits - they tend to drip very quickly and spray oil everywhere on the engine and cowling etc

Really does seem to be coming from the rear pushrod on the nearside. I have taken a good look at the assembly and the seals are covered by little metal cups, for want of a better way to describe it. Do I pull the rear one away from the seal and prod it to try and get it to seat better?

If that's where the leak is, then yes it is under the cup and that is the rubber seal you need to prod with a screwdriver to try and achieve a better seal

I had a poke at mine, didn't achieve anything unfortunately. My ex mechanic (2cv-er of many years) told me not to poke the seal itself but rather the spring that keeps it under tension. Worth a go though. I did gently poke at the cup, I could see slight movement of the seal.

Finally got around to taking a proper good look at the oil leak this afternoon. I removed the lower engine cowling to gain better access and once the engine was running I discovered what looks very much to be a hole in the rear pushrod tube in the passenger side of the engine. I'll try some chemical metal on the area and see if that'll work. Fingers and toes very much crossed.

Can you get something wrapped around the tube to hold the sealing substance in place? Pretty sure that'd work. Actually some kind of pipe repair tape suitable for a little heat would work maybe?

The tube is fitted tightly against the underside of the barrel so I doubt I'd be able to wrap something completely around the tube. I'm not working tomorrow, so I'll have a look and hopefully get it fixed.

Jonathan,
I repaired a pushrod tube which had a pin hole using a strip of aluminium sheet, Araldite and a pair of Jubilee clips.
That repair lasted until the Dyane was written off in a crash, some 20 years later...

Clean the surface of the pushrod with wire wool or similar, to provide a good key for the Araldite.
Shape the alloy by pressing it around a tube of similar outer diameter to the pushrod tube; 18mm
Open up the clips (18mm -25mm size) and feed them around the tube, ready to slip into position.
Coat the 'patch' with Araldite and hold it in position whilst the clips are tightened, then allow time for the adhesive to cure before running the engine.

Thanks Ken. I've been working on it this afternoon and I can confirm that the part of the tube with the hole in is the part that is tight against the underside of the barrel. I couldn't get a jubilee clip around that part. I also discovered that both of the local island shops that sell that sort of stuff don't actually sell chemical metal, so I decided to buy a small tub of exhaust paste and tried that. So far, so good. No sign of oil leaking out after a drive of around 15 to 20 miles at speeds up to 50mph. I know it's far from perfect and it'll probably fail fairly soon, but as long as it lasts till I can get some chemical metal, then I'll be happy. I'm looking to pop down south to Lerwick tomorrow, so will look for some.