I've had update 54 for a few days now and everything seemed fine until today as I found that after a while of adventuring from dimension to dimension whenever I tried to exit my tardis it wouldn't allow me as it said that my tardis was locked.

Problem has now fixed itself :)

If it happens again just place down one of the toyota control panels (either the left one or the right one). One of those controls whether the doors are locked or unlocked.