Firstly, I tried to send a small amount from an address inside the wallet where the BTC were, to the address at the top of the list - the wallet's heading address, and this worked.
Then I tried to send that sum to the Trezor, and followed by the remaining amount and in less than a minute the
BTC had arrived each time. Could it be that I needed to send a tx contract to the wallet from the wallet to get it working?
Anyway, that's over now, and a relief to the tune of 000's USD to my net value!
Problems now with BCH now, I can see coins with a read only wallet generated from the prv of this Linux wallet (doing this on the Mac though) but again there is an issue that seems similar in Electron.
I may need to create a Multisig wallet, the standard one won't do- address beginning with 1.. and make one beginning 3.. like the original Btc one.
I'll try the same process again with this, for the 00's USD it is worth...

THANK YOU