Clearly you are a business and ebay would expect you to be registered for VAT.
That said the turnover limit is now £90000 [not profit] so eBay wants you to send them your VAT number.
If you are not registered for VAT they would ideally like a letter from HMRC saying that [though I have never heard of such a scheme]. All you can do [and I am not sure if eBay will understand] is supply a copy of your P&L and a letter saying "my turnover is £75000 p a and I am not liable to register for VAT]. You could register voluntarily for VAT but that adds a cost to your sales which will - I'd guess - be mainly individuals who cannot reclaim the VAT. @wesellnumberplates
