Distant diagnosis can be difficult @Janetams1, but the real clue to the source of the problem is actually in your statement .....
Quote: 'It does intermittently when re enstalling try and set it up as talktalk.net as the host but I do put tiscali back in plus re do password.'
..... so the solution is down to you really, well done!
As I stated previously, [Apple] Mail is a sound application, but it can be a bit careless when clearing-up after incorrectly set-up, and deleted, accounts, but it is generally better to let it do it's own thing!
Thanks for posting back to let us know it's sorted.
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