Thanks so much Jay. The Vauxhall service ran the diagnostics today and tried to update it themselves.£160 for the privilege and they didn't get the part in. They say it's goosed and needs replacing. Now got to wait till 28th April. You really couldn't make this up! Almost £1300 for replacement, labour and vat. I will go after Vauxhall. Worth paying £100 for solicitors letter if it makes them realise I'm serious.
I really appreciate the information you've given me.