AR7000 Fails to bind to DX6e
 

Hi all
I am totally new to RC helis and have a second hand TREX450 that came fitted with a Spectrum AR7000 Rx, (but I noted no remote Rx).
I have created a new model for the 450 on my DX6e Tx ( a copy of my TREX470 setup, that will obviously need some tweaks).
I select the model on my Tx, power up the 450 into bind mode and get the orange flashing light.
Then on my Tx, select the bind option but get a "bind failed" message in response.
I'm totally lost with this. Is the remote Rx essential here, or will it work ok without?
I have three models set up on my Tx, the TREX470 which achieved a bind with no problem. NEXT simulator with Spectrum WS1000 dongle on my PC, which also achieved a bind with no problem. Then I have the TREX450 with the AR7000 Rx which refuses to bind. What am I missing here?
Thanks in advance for any advice.