Hi guys. Thanks for the replies.
I've changed the internals of each injector for new - this is just the lower part; needle and nozzle. They are all Bosch - made in France and came wax coated. I'm pretty sure they are good quality replacements.
Yes, I have replaced all the heat shields.
Buy no, I've not 'set' them up, other than putting them back together and in the engine.
So, I've decided to put the old cores back in, made sure they are centered and refitted these into the engine. Two of the new ones I fitted were slightly off center - you live and learn - the same as these needing properly set up to the correct pressure : )
I regret messing with these as it was running OK with the old injectors to begin with. I just thought it was prudent to replace the injector nozzle / needle as part of good servicing since the original setup could be almost 40 years old.
I also appreciate that revving in my video is not something that would naturally happen under load / normal driving.
However, having said all this, I'm a little more reassured that my engine hasn't developed some terminal fault and, once I've sorted this, should be good and strong.
I added a few photos of the camper / engine to my other help thread
HERE if you're interested : )
Thanks again for the replies.