I have used the harrow branch to print b&w from true b&w negatives, and
have recieved back prints with grey not true b&w,they appear ok if
printed high contrast.

I e-mailed the watford branch which told me they use kodak royal paper,
being the same as the ones I recieved at the harrow branch, they
informed me that I won't recieve the colour cast on there prints.

Being a franchise, also using mini-labs with kodak royal paper, which
is colour paper, surely each branch must have the same results.

I proberly goto a pro lab like sky, metro, team photography etc...