Good idea, will bring it up at the next MTM, perhaps a job for the new commercial manager ?
Couple of years ago I (personally) bought and paid for a batch of tyres from a dealer in Witney thinking that it would help our club members. Spent a couple of grand (of my own money before anyone kicks off !!!), collected them and stored them in the dark at my factory. Took ages to get rid and they were popular sizes and a popular make.
I think it is down to the logistics in a way; not so good for people to buy tyres via the post as they then need to get them fitted, normally this negates the saving at least to some extent.
I'm sure that Grahame will have general tyre discounts with a variety of potential outlets on his list of "things to do" but will, as stated, bring it up at the MTM and take it upon myself to report back to you afterwards.
Does that make any sense ?