But once the seller has agreed to sell to the buyer at the price verbally agreed the seller can not sell to higher bidder
This happens in property selling - gazumping. Which is not illegal in England.
Houses and land in England are all sold ‘subject to contract’ and so the sale of goods act doesn’t apply
Slightly different in Scotland
Could this also apply to goods like this, if the words 'subject to contract' were spoken at the time of the offer and acceptance or is this the actual contract and no further contract can be made?
What is required for a contract to be made is:
1/ an offer and acceptance of that offer. The acceptance must agree entirely with the offer and must not be conditonal
3/ the intention to contract
There are other requirements but not relevant here.
Subject to contract or indeed subject to anthing else including swmbo's approval means that there hasnt been acceptance in full.
The Sale of Goods Act is irrelevant