Anyone letting a property in this manner has obligations under the equality act to make 'reasonable adjustments' to accommodate access needs, as I'm sure you're aware.
They are also obligated to provide clear and accurate details of how the property is, and isn't, accessible, under consumer protection law.
You say that the property owner referred the booker to their access statement. When did they do so? If this information was readily available on the website listing, or was provided upon request prior to booking, then (assuming it was complete and accurate) they have likely fulfilled their obligations.
If it wasn't readily available, or only provided at the point a complaint was made, they may not have met their obligations. Same goes if key information was omitted or unclear, for example, noting door widths where these would prevent standard wheelchair access.
You say the booking was made through a website, but you also say it was made directly with the property owner. If you have used a third party website to make the booking, you may be able to raise the issue with them if the property owner is not cooperating/communicating, or is disputing your complaint.
If this isn't the case, then you would need to pursue a small claim against the owner.
'Wheelchair friendly' isn't a term with a rigid legal definition. The question is, did the owner provide clear, accurate and complete details as to how the property is (and isn't) accessible, so that a reasonable person would not be misled when booking?