@atkuna can you break the jars?

Update. Same issue with two more doors.
One in Anderitum Hideout, but not essential, just inconvenient.
The other in Dover Fort, critical as it is only access to skill book.

@pfroddam Update.
Being a bit OCD, I went back and eventually found a way in.
The chest said I need to find keys for all its locks.
I grabbed a second key that was inside the building.
Still unable to open door to house or locked chest.

It appears there is a problem with some of the keys needed to open locked doors not appearing in inventory when picket up, making the doors unopenable.
In one case, the Londonium Bureau, it was a nusience, but in the second case, it has left me unable to access a chest containing equipment.
This second key was to a home in Lunden, East South East of Londinium Stadium, and just the other side of the little waterway that runs from the swampy lakey bit in the north down to the thames river. The key was sitting on a barrel just near the house with the armour chest in it.
The house also has a barred door.
I have checked the area as thoroughly as I could, over an hour or more, and could find no other way in.