I am happy to say that Wifey & I visited the banks we could not get to acknowledge her existence today and all accounts are in the process of being closed. The most difficult one was TSB (who WE bank with) and so we went through a whole rigmarole for the sum of <£150 in the old gal's dormant account with them.
So that parts is all done. Now we move on to try and get probate initiated.

Here's a conundrum; part of the determination whether you need probate or not is the complexity and value of the estate.
Liquid assets the old gal had were <£50k and the domestic chattels are just scrap. The house is seen by the land registry as being worth 500k BUT, it is falling down and has already had 2 goes at being underpinned and is still cracking up and really is only worth the value of the plot for a redevelopment. So what do we say to HMRC/Probate peeps?
My view is that we get a local estate agent to value the place (as is) with the knowledge that it is blighted and then get a surveyor to write a report stating it is structurally unsound.