The Margin Scheme on second-hand cars

FAC

Hi,

Recently we engaged with a client who is second hand car dealer. I am going to register him for VAT.

They mainly buy second cars from Newark Motor Auction and British Car Auction.

British Car Auction Invoice include 2 items
Car price 2000 No VAT
Buyer Fees 189 No VAT
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Total paid 2189

Newark Motor Auction Invoice
Car price 2000 No VAT
Buyer Fees 100 £20
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Total paid £2120

As their invoice mention, both of these auctions use Margin Scheme. One of them charges VAT on buyer fees other does't.

My question: should buyer fees be included in purchase price when calculating gross margin or they should be considered as over head? Newark Auction charges VAT on Buyer fees, should this VAT be treated as standard VAT in return?
I read VAT notice 718/1 it does not mention fees and commissions.

Thank you in advance for your help.