yes we had same problem on our plus 4 year 2000 car turned out the rubber filler hose was beginning to fail put in a new one and it fixed the problem see this link for my photos
https://flic.kr/s/aHskkTxRYp Filler hoses from around 2000 time were an issue I believe - deteriated quickly
I'm guessing it was the quality
Most Zetec engined Morgan owners I know, including mine have had to have replacements
Someone told me at Gaydon that the factory don't get the replacements anymore but it looks like Librands still carry the replacement for Zetec engines cars which have the problem
