1981 Autosleeper, originally a 1.6 diesel, had a 1Y conversion done last year with a 1.9 from a '98 Seat Ibiza with low mileage. Sump, etc., from original engine used in the conversion.
I have a small oil leak at the bottom of the oil filler tube. You can see the tube in this photo: -

A long plastic filler pip mates with an aluminium elbow joint, which in turn mates with the sump. The leak seems to be coming from the bottom of the elbow joint where it mates with the sump, so my guess is that there is a gasket between the two which is failing, and which i need to replace. However, i do not know which gasket i need to buy - can anyone advise me, and perhaps tell me where i might get hold of one?
As an aside, what appears to be a crack at the bottom left hand side of the plastic part of the filler pipe, isn't.
Also, there is a small 'weep' of oil from the drain plug, which can be seen to the left of the filler pipe in this photo: -

I believe this should have a copper washer fitted to seal it - can anyone advise where i might get hold of one?
Many thanks in advance for any help anyone can offer.