What is the problem with that? Let people have the choice of whether to pay up to £1,000 a year to park - or get a bus season (circa £400 a year) and travel that way. Or cycle. Or walk.
I go to Stevenage a lot (by car, it has to be said as it's mostly to the retail parks) and there seems to be a pretty good network of buses operated by Arriva, Uno and possibly others. However, many don't run very late into the night - and that can put off commuters who may work long hours, work overtime or simply get delayed.
My local bus was going to stop running around 7pm before the local residents, a councillor and then my MP helped get it restored to 11pm, seven days a week. If it had been cut to 7pm, there would be countless times I'd finish work and get back to my station after it had left. Even working until 6pm would make it tight, and I quite regularly worked until 6.30-7pm.
If there's a demand for car parking, build a car park. Then, if you want local people to use public transport, improve the options and people will choose the most convenient. Meanwhile, the car park can be used by people who have driven from further away (and possibly at a time when you wouldn't expect buses to be running) to go a lot further away than merely commuters going into London. Who knows, EC could even offer free parking for people buying open returns, or at least a nice discount.