Sorry to hear some toe-rag has stolen the pistols. The boxes and tin certainly do retain value, which in my estimation should be...

LP53 box and accessories: No less than £75 as these items can easily add £100 to the value of a nice LP53

The Webley box is an early post war variant and ought to be worth around £60-£75.

The tin - around £60

That auction site is probably the best bet.

John