CGT on site transfer to buy new site

Hi, hoping someone may be able to help us. My OH inherited a site back in 2006 but we never built on it and never got planning; no payment or tax was due on it as it was below the threshold. Between then and now, we moved and find ourselves with the option of buying a site close to were we now work. We talked with the vendor and reached an agreement of our site + payment for his site. Before we go and engage a solicitor I wanted to check if we would have to pay capital gains on our existing site since its been used as part payment.

the disposal of the site will indeed count as a disposal for CGT purposes.

whether any CGT is actually due will depend on whether the site has increased in value since it was acquired.