I live in Hull & the nearest campsite I know is at Burton Constable near Sproatley (East of Hull). It's about 10 minutes drive from outskirts or about 30 minutes to the town centre.
In the end, we didn't go in February, but we did spend Holy Week at Burton Constable - and very much liked the site (although we enjoyed it less so for Easter weekend when it was full to overflowing!).