Is it an industrial version?

As has been posted, the Centaurus was a more reliable engine than other British ones. When built properly.
Typical examples of reliability:
Civil Centaurus max TBO (Time Between Overhaul) was 3000 hrs and Civil Merlin max TBO 1000 hrs.
Setting up the valve timing was intensive work though. The good thing being that you didn’t have to adjust them anymore.
I would imagine fitting American engines was due to their availability of spares. The swept volume of the 3350 is slightly higher (1 ltr) and being turbo-compound, more power available. It is also slightly more reliable, the figures given being in the range of 3500 hrs TBO.

We are in need of some hydraulic oil out of shelf life would be OK any body got any leads.

Do you know any service technician who does work on internal transport in warehouses. Reach-trucks and pallet trucks in the deep freeze houses do use an OM15 equivalent (41).
They also change it regularly. You might get some good but used oil for nothing..

My first experience of seeing how fast the Lightnings were was during an exercise at Binbrook in ’77.
Two Buccaneers were intercepted by an F3. The Bucc’s split up thinking they could get away. The F3 just nonchalantly followed one, got his gun-camera kill and turned towards the other. I heard the rumble of the reheat and it just shot, and I mean SHOT behind the second. He casually followed it for a few seconds then pealed away. Those kites have more legs than a centipede……

Do you have photos of the rivets?

The B57’s had even funnier engines…