OK, so they've re-offered the discount, but there is some real tosh in their letter
"It remains the responsibility of the driver to check in advance what the parking provisions are. This can be done by researching online or asking the people you are visiting"
and
"There are parking provisions throughout London, so checking parking provisions or restrictions in advance of a visit should be common practice"
Really ? So where is all this written down as a requirement of motorists ?
The motorist should be able to rely on traffic signs at his destination. That is the legally mandated method of informing motorists of restrictions defined in traffic orders. So when I decide to visit my cousin in Peebles, I need to go on-line to check the Peebles traffic restrictions ?
I think I'd be strongly tempted to take them to London Tribunals, but it's your money not mine.