What is the branch address for Barclays Bank sort code 20-14-42?

There is no such bank, Barclays or otherwise, with the sort code 20-14-42.

The nearest sort codes, numerically speaking, to 20-14-42 are: Sort code 20-14-34 which is the branch of Barclays based at Leicester, De Montfort Street, LE87 2BB, England; or, 3 Kingsland Grange, Woolston, Warrington, WA1 4RW, England. 

What is a Sort Code?

A sort code is used by British banks to direct route money
transfers between themselves via their own clearance organisations.The sort code is usually three pairs
of numbers, e.g., 54-21-06. This identifies both the bank and branch.  You can often tell which bank the code relates
to by the first two digits; in this case of ’20,’ this indicates a branch of Barclays.
Six-digit sort codes were brought in during the 1960s as banking
increasingly relied on computerisation, making banks easier to identify
themselves and each other. 

If you're feeling lost, why not wander down memory lane with these famous Barclays adverts from the 1990s?