GB VAT Query?

Hi,

I’m setting up a new directory for local bike shops and looking to charge £100 + VAT per annum for listing (I am VAT registered).

Having integrated everything OK (AFAIK), when I create a test listing (as a customer/shop) and go to the checkout screen it asks me for to validate my VAT number. On entering my vat, it removes the VAT element/charge for the invoice.

I’m not sure I understand why that is required or happens? Surely as a VAT registered UK business I SHOULD charge VAT to my customers so I would expect my invoice to be £100 + £20 VAT, not be zero rated. Surely if my customer/bike shop is VAT registered themselves then they can claim back the VAT i charge on my invoice accordingly? I’m only intended to promote/list UK located bike shops…

Please explain further or if I have missed a setting to remove the VAT validation box from the checkout screen. I perhaps have misunderstood the VAT system, but I know I don’t charge VAT to other countries such as Malta and Gibraltar in other areas of my business..

Thanks

Mike