I have just received a call back from customer services.
Very quick.....but I could barely understand the 'dark foreign johnny' on the other end of the line. Apparently next day delivery is an aspiration rather than a guarantee. In other words they will do their best but can't promise next day (or any day) delivery.
I imagine they can't guarantee anything due to the vagaries of couriers - I will say though that we use them a lot and 99% arrives next day, often evening if thats a Sunday. For us very good value.
Amazon offer free postage on orders over £20.
So, in effect, I would be paying £79.95 for some dubious quality viewing with one or two exceptions.
Free delivery is 3 to 5 days, so if speed is important to you (which it is to me) then thats what your paying for