I'm no legal wizkid but in my book,'bespoke' means made to specification. It appears to me that the product offered is 'off the shelf' and definately NOT made to your specification, and therefore is not bespoke.
A buyer cannot exempt himself from the law and that clause I feel would not stand up in Court.
Question is..Do you want to take the risk of possible hassle you might encounter if things go pear shape.
Even if the Law is on your side do you need the foreseeable problems.
My suggestion...speak to the vendor and have the Condition removed. If he refuses...go elsewhere