Holds the travellers' cash in the square mile of the City of London presumably (5,4)
I believe the answer is:
money belt
'mile of the city of london presumably' is the definition.
I can't tell whether this definition defines the answer.
'holds the travellers' cash in the square' is the wordplay.
I cannot quite see how this works, but
'cash' could be 'money' (I've seen this before) and 'money' is present in the answer.
'square' could be 't' (a T-Square is a technical drawing instrument) and 't' is located in the answer.
The remaining letters 'bel' is a valid word which might be clued in a way I don't understand.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for money belt that I've seen before include "Item worn to counter pickpockets" , "Cash concealer" , "bucks are safe in it" .)