Another alternate clue for 5a
Whilst staying here the Krays crazily wrote of home
You still have all the elements of original clue.
That the Kray twins were among the last to be imprisoned in the Tower.
You now have an anagram indicator (crazily).
Crazily wrote = tower
You also have 'of home'. Home to the Krays = London = of London, as further help to arriving at tower as an answer.