I have read the Portas report - and you're right. It is particularly relevant to shopping centres such as Marple.
Unfortunately, the Loyalty Card scheme was just to expensive to continue (I understand it wouldn't have been acceptable for Portas funding as this scheme was pre-existing the Portas Pilot application process and they are looking for new initatives).
With the Loyalty Card scheme costing circa £1,400 / year to run and administer it was committing too much of the MBF's limited resources for the relatively small number of users.
However, the MBF is still being pro-active and is working on a new Car Park Reabate Scheme that should go live in the next couple of months - a scheme that should cost less than the Loyalty Card per year yet benefit a larger proportion of visitors.