I have just agreed with an Inspector of taxes -the answer to the above.
Bitcoin Mining is not a trade.
Any Bitcoins "mined" will only be taxed when they are sold and converted to Fiat Currency and would be subject simply to CGT. The mining "cost" will be seem as the cost of the investment, which means losses potentially would be relievable.
Bitcoins and other cryptocurrenies will only be taxed when they are sold and then subect just to CGT.
This all seems a good outcome and I wonder if any other accountants have agreed similar terms from the revenue?
Thanks in anticipation of replies.