Can anyone help please?

Hi Folks, after a very stressful divorce,lasting 3 yrs !!,I am trying to move on as they say. So I am trying to complete a project I started a long time ago, way back in the late 70s, when I dug up a Lancaster engine from P.D.201 from 12 Sqrn. I was able to remove one piston and con rod, two inlet valves ONE exhaust valve, and the two spark plugs. That just leaves me to try and obtain the other exhaust valve. I have tried ebay, and also Peter Grieve, but he has sold all of his. Has any member a spare exhaust valve they could sell me please, so I may complete my display.
Many thanks
Lincoln 7.