Through the serendipitous way that the internet works I've just found a link on the twice-weekly diocesan email bulletin to Help2Park's web page that shows Leicester city centre's car parks with (this is the clever bit) an up to date report on how full they are.
It's now 9.34pm and I see that should I want to venture "up town" I can choose any of 834 places that are left at The Shires, or one of the only 180 left at St Nicholas Circle.
What about trying this for churches? Hover your mouse over St Paul's at 09:58 on a Sunday and find that there's only 14 places left... Better drive on then to St ----- , where there's a good 198 spaces in the pews! (I'm making this up).