Thanks for the replies DashcamDPR and DT MI. I have contacted Cobra regarding lack of information regarding the model ie, no mention of model number on the outer packaging, or on the reverse, it only says it is a Cobra driveHD Dual View Dash Cam, and the other features. I went on to the Cobra site and choose the UK option and the only Dual Dash Cam product was identified as CDR 895, this was the model I took to be mine and obviously downloaded the the firmware update, and installed it. Only when it was apparent that the update had failed, I looked for a reset button, and there on the base of the camera was a tiny (10mm x 4mm) label giving the model number CDR905, serial etc. There is no CDR905 on the UK site.
So I will wait and see how they reply, and I'll let you know. I bought another one as all the cabling was ready and it all works fine - expensive episode 2 x £149.99