There are four spaces for motorhomes in Sainsburys car park, free for two hours. They are not reserved so may be in use by other vehicles but there wouldn't be a problem if you take up 2 normal bays.
The Shrovetide car park is a bit bumpy but has plenty of space for motorhomes and you could stop there overnight.
Aldi car park is almost never full and is easily accessible for motorhomes - you would have to park over 2 bays.
There is a coach park by the leisure centre - the spaces are almost always empty but technically you are not allowed so this is strictly at your own risk.
There is room for a motorhome outside the cemetery.