Early 3000M - overflow bottle query

[MattT350T]

Hi all.
I have the original Part (19) in the cooling diagram.



Once fully cleaned up, I would like to re-use this following my under-bonnet restoration and partial upgrade.

Unfortunately the seal/lid is rotten through and will not do the job. Is anyone aware of a stock item from a specialist or anywhere for that matter that I could use as a replacement please?

[phillpot]

Looks similar but cap maybe larger diameter, unless you used the whole thing ?


Tudor bottle