So... I've cashed out enough Bitcoin to pay off the mortgage and pay 28% capital gains tax on it. I spent £10 on Bitcoin in January 2011 when you could still buy them with Paypal.
So my first question would be why did you choose to pay 28%? AFAIK 28% is the higher bracket tax on the sale of residential property. Other assets are charged 20%.
You have it all here:
https://www.gov.uk/capital-gains-tax/ratesIs there any point in going to one of these firms? It strikes me that I might end up paying them a lot of money for advice on a straightforward issue. I know there is a suggestion that sufficiently speculative transactions count as gambling and are therefore untaxed. However whilst it feels as if I've won the lottery, another part of me feels that it was just a particularly good investment and should have been treated as such. In which case, simple..?
Yes, I think you should consult someone if you have a lot of money on the line. For a mere £10k in BTC you have potentially saved £800 if I'm right about the tax rates that apply in your case. You can always ask them how much they're charging before you decide.
Also, if I were you I'd divide my assets into smaller parts to make sure I'm within the basic rate band each year (£33,500) and pay 10%. If you have a lot of money on the line (100k) dividing it into 3 years like that can save you £10k.