Unreasonable restriction?

[G7ivp]

I took my wife to a retail park recently. We are both disabled and walking is slow and difficult. We visited several shops, had a coffee and collected a prescription at Boots; a busy visit (I was queuing in Boots for nearly 30 minutes). On returning to the car I looked at a sign that listed the terms and conditions of the car park and was shocked to see a limitation of 3 hours, after which period a penalty charge would become due, and I am sure we exceeded this. Now, 3 hours may be sufficient for the able bodied to do all they need to do but not those with restricted mobility. Should a 'Reasonable Adjustment' be made to exempt the disabled from the 3 hour rule? How can I challenge it if I get a penalty charge notice? It certainly put us off visiting there again.