Coolant leaking into oil galley/return

Hello All,

I have a Vogue which I have just bought with suspected valve damage, I striped the engine and sent the heads to be checked and repaired if needed.

The heads had been skimmed and one had two new valves installed, when I had them back put all new parts on and proceeded to to fill with water, after a few minutes I saw water leaking from the oil pan.

I got underneath the car and noticed that the water was coming down a return pipe near the front of the engine on both sides in the sump. I removed the valley pan to see if there was a leak anywhere by there.

No signs of leaks anywhere on the valley pan so, I decided to try and put water down the two water ports at the back of the engine where the valley pan sits, again after few minutes the water started to leak again. So now I am at my wits end trying to figure it out. Can anyone shed any light on what it could be and how to fix it please?I know I could use K-seal or steel seal but the engine will not run. Is there any other way to fix it?

Please see attached pictures.

Thank you in advance for all your help.

Chris.