If the wheels/tyres protrude further than the arch then they are an MOT fail and not legal. If you had an arsey copper they could have you under "Construction and Use" and even issue a prohibition notice meaning you'll not be able to drive any further and you'll be stuck with recovery costs and potentially a long walk home.

Most plod will prob just advise you to sort it and give you a VDRS notice to change the wheels if they spot it.

Sounds like somebody sold you Pegeout offset wheels