HI Rob,
That looks like in very good condition for the age and being in the UK.
As a side note what color are you using in a modern paint? The reason I ask is my car was possibly this colour if it is the Mist Green as listed as a original colour for a early 1952 tourer.
OK I get what your saying on the X and what it would do for strength. Do you think it should be for the whole side of the car or just the door opening? I plan on a stiffener across the car at the "B" pillar to keep that shape as well.
Looks like I need to get started with temp frame work to keep the car in shape.
TX
Mr fixit
Chris