A cynic writes:
Windfarms sell to the wholesale electricity market at the price their customers are willing to pay - so it is the same price as electricity from gas, nuclear etc. They can also export to our European neighbours who are also willing to pay the price, and maybe a slightly higher price.
Some older windfarms agreed guaranteed price deals with the government so that they would receive subsidies as the price they needed to be economic was say, £60/MWh when the wholesale price was lower - say £50/MWh. When the wholesale price increased above £60 they stopped receiving subsidy, but some of the earlier contracts never envisioned prices going so high and there was no repayment to the government. The windfarms keep all the extra money.
Most windfarms have deals where the government pays subsidy when the price is below the agreed price, and the windfarm pays the government when the price is above the agreed price. I can't find data about how much of the "extra" price the windfarm keeps and how much goes to the government - it is likely to be "commercially sensitive" (ie. embarrassing to one or both parties)
Some brand new windfarms are signed up to similar deals (and actually with a lower guaranteed price), but there is a loophole. To supposedly allow for building delays and commissioning etc, the guaranteed price doesn't come into effect as soon as the windfarm starts generating, the windfarm company can delay the onset of the contract. Of course at the moment all the contracts are being delayed whilst the windfarm rakes in the money at the massive wholesale prices of today.
As to actual prices, as recently as 2020 wholesale electricity was £50/MWh and it is currently running at £200 to £250/MWh. Deals signed for offshore windfarms (due to come online by 2026) in the recent auction have the guaranteed price as low as £37/MWh for 15 years, which shows how much someone is making!