the address it provided was not in my list and had zero txns - is it possible that the address is a different format from one of the other addresses that are a watch only then?
No. Electrum can only select an address from the list of addresses you have given it. If you go to your Addresses tab you should see that address (Tip: you can go to that tab and press ctrl+F and then start typing in the box that appears to search the list).Quote
only edit to the screenshot is i blacked out my wallets name - as you can see it is a "watch only" wallet yet I clicked "new address" and it created an address that "expires in 24 hours" I also do not understand that - how can an address "expire" or is it the request that "expires"?
In Receive tab you only create payment requests not addresses. These are basically Electrum's way of "keeping an eye out for an incoming payment to an existing address". The "request" expires (not the address) meaning Electrum stops looking for an incoming payment, however you can still receive payment and see it in your wallet.ok so that address was ALREADY there then is that what you mean?
in that case I just need to track where I got that address from and the key that went to it.
It would have been generated by bitcoin core on an airgapped system and then put into electrum as a watch only.
thank you for your help. I just need to do some digging.