Can VAT be charged after a contract has been made for spectacles?

I went to an opticians had an eye test and agreed to have a pair of glasses at a total price of £220.  They asked for a £100 deposit which I gave using a credit card.  They will be ready in 10 days.  As I understand Contract Law.  A contract has been made here with offer, acceptance and the deposit as consideration.  No mention of VAT was made at any time.  Therefore, when I collect the glasses and pay the balance of £120 they cannot suddenly try to add VAT to the sum due because the contract was for £220.  Am I correct?

 

Thanks

Glynice

Alasdair Taylor's answer to Can VAT be charged after a contract has been made for spectacles? (115101972)

Certainly in the case of a B2C sale of a product, if an English law contract is made for an agreed price, that price should usually be assumed to include VAT.

This is the case even where the sale is outside the scope of the Price Marking Order 2004 - for example, because the products which are supplied in the course of the provision of a service.

One issue here may be evidential. If you have any documentation specifying the price, that will certainly help.