Many thanks for the further input. Apologies if the info was not clear or consistent but things occur to me (OP) afterwards....
Going back to the situation when i left the car for a period when it rained heavily: i tried to start it as usual and there was an initial catch and instantaneous faulure to coninue to run. This happeded again yesterday after i cleaned the wells out, cleaned the plugs and fitted the new gaskets and lubed the cams up a bit too.
ref the salient pionts in the last two emails:
"So disturbance of the cam sensor connector whilst fitting the seals didn't cause the original issue. The fault was already present."
yes, i agree, however the issue ast time this happned (apart from the starter "light" noise) was due to the water in the wells; hence my actin this time.
"Something else is wrong". see my comments within in italic:
From your description it sounds like the starter motor is not engaging and spinning the engine. Have a look from the front whilst an assistant turns the engine over. Can you see the auxiliary belt moving? Put some chalk marks on the belt if it makes it easier to see. perhaps it is not engaging at least for long enough to catch. I have no assistant where i left the car, sadly. good idea, will have to do that eg using phone in video mode
What's the rested battery voltage? 12.6v, then after a few tries 11.8v; now recharged to 12.6v
What's the battery voltage whilst cranking? You'll need an assistant to turn the engine over? do not know, i can put MM on "max" funtion and spin over as no assistant
And is the car an auto or a manual? auto
And what did you use to check for fault codes? Scanner Pro (ie odbII reader and re-set. I have a better item here at home so can use that next time i go down to the car.
Foam: had no time to remove that but have left top of engine covered in plastic bags pending return. foam seems attached by push on toothed washers on studs; is that it to remove the foam?
New cam sensor (Delphi), plugs (Bosch), coil pack (Bosch) now purchased.
Action:
1 video the aux belt with chalk marker,
2 test for codes with other scanner
3 then new Plugs and new coil pack will be fitted at same time
4 Then if no joy, the cam sensor will be fitted (back probe the old connector for electrical connectivity first).
Is that acceptable as a logical approach?
Many thanks again
RDS