Maybe you need to lose weight? ;-)
Blocking other vehicles in is 'causing an obstruction' and therefore an offence. Although many parking matters are now dealt with by enforcement officers employed by local councils, 'causing an obstruction' is still a police matter. That assumes that at least one wheel of of the offending vehicle is on the public highway. The situation might be different if all of the vehicles are on private land.
Irrespective of whether the vehicles are on the highway or on private property, it might be worth having a word with your local community constable. If he/she doesn't seem interested, say something like 'People are getting really annoyed about this. I'm worried that someone might eventually take the law into their own hands'. A hint of possible violence, or of criminal damage, might spur the officer into speaking to the offending driver about the matter.
Chris