I didn't explain that very well! to simplify

1 I had a Bitcoin core wallet stored offline on a USB
2 I didn't want to expose this to the web, so imported it to an air gapped machine.
3 The balances show in this wallet, but they are unconfirmed as this machine does not have the blockchain
3 I have set up an Elctrum offline wallet on this air gapped machine
4 I have set up an Electrum watching only wallet on an online machine
5 I have checked blockchain info and all the inputs and balance is showing for my receive address
6 I go to coinb.in and create a new transaction
7 coinb.in sees the correct balance and inputs
8 Raw transaction is created and taken to air gapped machine to sign with BTcore
9 Bt core gives the error "no inputs found or already spent" when I try to sign it in the debug window.

I think that explains it much better than my previous post!

Grateful for any suggestions!