Martin
Presumably, the property is now registered in your name and there is no inheritance tax outstanding, from when you inherited it.
CGT will be calculated as the difference between the value of the property when you inherited it and its market value now @ 25%.
(If the disposal price is lower than its current market value, then the market value needs to be used)
In addition you may be entitled to a number of reliefs
1) an annual personal relief of 1270 against the gain
2) If you have lived in the property as your principal residence, since you inherited it, you will receive relief for those years
3) you may be entitled to some indexation relief depending on what year you inherited the property
I hope this helps
Best wishes