Oily,
Yes all pipework has just been removed and dry sump tank emptied, including removal of blue plate.
Update on what I have done tonight - however I haven't solved the problem!!
So I knew confidently re levels and pipe work, I emptied the oil removed the hoses, check and cleaned then and removed filter. Reconnected everything.
I also replaced the the Mocal catch tank with the old plastic catch tank.
I filled up the DS tank to a level which measured 12 inch from the bottom of the DS tank.
Started the engine - 64 psi of oil pressure and nothing in the catch tank.
Ran the engine for around 30 secs then switched off.
Checked the level in the DS Tank and it had, as expected, reduced as the oil had being pulled around the system. Topped it up until it measured 12 inch from bottom.
Started the engine again, pressure OK and nothing being blown into the catch tank.
Repeated and added a touch more oil to 13.5 inch - when engine next started a small amout was blown into the catch tank but pressure was still fine.
Went out on a small run, after 2 miles oil pressure drops, hovers for a while (20 secs) around 15 psi then back up to 64psi.
Turned for home, as approaching oil pressure drops again hovers around 9 psi (maybe 30 secs this time) then back up to mid 60's psi.
Gets home swaps sender and checks levels nothing extra in the catch tank, approx 12inc in the DS tank.
Goes for a run exactly the same happened.
So in summary:
The change in catch tank may have addressed the expelling of too much oil (but more likely down to only very short runs).
I am now getting intermitent drops in oil pressure. Some may think this is down to a sender, however I will disprove that one when I borrow one know to be working tomorrow.
Is this now pointing to the oil pressure release valve coming into operation. If so what causes that?
Final test tomorrow (apart from the 3rd sender) is to unplug the cam vents to see if they have an impact.
If that doesn't work then, then I heading back to MK. ☹️
Northern Banana.co.uk