Hi All and a big thanks to all, from your replies I have the following update on the SR1 powered Dumper [now christened Damien].
In accord with your notes and others on this forum I have been working it hard.
With poorly fitting exhaust/inlet manifolds for the sakes of a couple of minutes I thought I would fix this. Having removed them I could easily see a 'matching pair' of fuel leaks from the fuel filter assembly bleed screws. Seals perished. Did a temporary fix by cutting 2 from an old oil container lid insides. Promptly ordered and received a new fuel filter set. Thanks to my parts supplier.
What a state that filter was in! The new fuel filter (and a workout) gave rise to a slight improvement in performance but this may have been placebo. Next, snake oil time, I added a good dose of diesel 'injector cleaner' to the tank (just in case it helps).
After seeing the fuel filter and before the recommended hydro-surgery I thought I would change the oil. I changed the oil temporarily for some synthetic 10/40 stuff I had lying around for years. Then I warmed it up and with fair rpm's began to gingerly pour water down the intake from a bottle fitted with one of those drinking on/off valves. The crap vomiting from the exhaust seemed endless so I ended after about 0.5 litres.
I checked the oil later for water and there was none
I changed the oil again, this time including the filter. Just unbelievable that any oil was flowing around, even the filter was disintegrating with age. Again the seals were hard or shot.
So with fuel flow ok good supporting oil and confident water was not getting into the sump I warmed it up vigorously and with serious rpm's began to pour water down the intake. On occasion I over egged the water a little (that's quite a splash), heard the engine rpm fall off so backed off and the motor picked up again. This had prompted water to be spat from the exhaust along with a bit of oily residue. After a little over a litre I ended the session.
The effect was definite this time. Previously unable to attempt ANY rising incline as it would falter and stall now I am able to move across the site in 2nd/3 gears with impunity. That's a big improvement in performance.
I continue with the odd pouring and iaw glort's thinking on continued hydro-therapy I need to rig something up (linked to the rpm) to run this for a few hours as I go about over the next few months.
Still no signs of water in the crankcase.
It may be I am further up the learning curve but it now starts first time even after 3 weeks off. So I don't believe there is a compression issue.
I still get blue smoke and some black spit mostly after idling for too long. Exhaust or inlet I have no idea but Listard_JP2 does have that simple logic and the designer/design managers didn't put a seal on the one guide for nothing.
BUT is it possible to change the inlet valve guide seal without removing and splitting the head? If this is not possible then the solution would be head off for a top end overhaul.glort could be onto a win-win here highlighting the cunning of gremlins to exploit unintended consequences.
Thanks to all again.