We bought an old bungalow in 2009 on a large plot together with 2.5 acre field across the road.

We bought them both at the same time (as one), so therefore paid stamp duty on both. We then developed the bungalow into a much larger house.

Now we are older, we want to sell the field to pay off a small amount of mortgage left.

Can anyone let me know if we will have to pay Capital Gains Tax or other tax on the sale of the field? If so how much would this be?