Thanks for your question
Without taking into account any capital improvements or legal/estate agent costs to sell, we have an initial gain of £1.1 million which will be divided by the four of you, giving each of you a gain of £275,000
The first £10.600 of each of your gains will be exempt, leaving £264,400 liable to capital gain tax.
If any of you are a higher rate taxpayer (so with annual income in excess of £42,475) then this gain will be charged at 28% = £74.032 capital gains to pay, but if your annual incomes are less than £42,475, then some of the gain (the equivalent of the basic rate band unused) will be liable to 28% and any remaining gain at 28%.
Each of you should alert HMRC once the sale has taken place, so capital gains can be declared after the end of the tax year.