Hello and welcome to the site. Thank you for your question.
Supplies of land and buildings, such as freehold sales, leasing or renting, are normally exempt from VAT. This means that no VAT is payable.
However, you can opt to tax land. For the purposes of VAT, the term ‘land’ includes any buildings or structures permanently affixed to it. You don’t need to own the land in order to opt to tax. Once you have opted to tax all the supplies you make of your interest in the land or buildings will normally be standard rated.
Based on what you have stated, you had not opted to tax land notwithstanding the fact your business is VAT registered.
The solicitor is right in saying you don’t charge VAT on the sale price as it is evident from your communications with HMRC.
You will not have to pay VAT on the sale of the property, based on facts provided.
More information on this can be found here (Sections 1.3 and 2)
I hope this is helpful and answers your question.
If you have any other questions, please ask me before you rate my service – I’ll be happy to respond.