Depending which part of Cardiff you want it's 5/6 miles from the parking. So likely another 1.2 hr plus after waiting for park and ride bus etc and lugging shopping back won't make it popular. I'd have made a whole heap more sense to me to have run a wire from the solar arm into town and wired up a multistorey car-park?
Not that i can ever see myself going down to cardiff from my bit of wales. And since it's park and ride you can bet they'll be slow chargers to get that many in. Still I'm sure someone will make a few squid out of it and hail it a success whenever a match is on and it gets used.