To me this is a typical supplier and buyer issue - The supplier puts a product out, gives them a price for maintenance and then gets annoyed when they don't take the maintenance offer. When the buyer maintains the product themselves, the supplier doesn't want any part in the blame for the product going wrong. Then they need to replace the product, the supplier offers a good deal with maintenance for set period. Everyone is happy, until the contract runs out, then the loop starts once more.
"But since then a significant amount of additional material, which is not Polytrack at all, has been provided by alternative suppliers and the composition of the surface has changed significantly since it was installed." You wanna see the mess on Blackpool beach they made taking all that sand away...!!!
Mess of a surface and heading the way of Southwell in which course form is essential and the form book elsewhere is of minimal help. These all weather tracks receive more use than any turf track and so you would think that the maintenance aspect would be held in more importance than it clearly was at Wolverhampton.