As a British citizen I was surprised you mentioned guidelines of tipping beyond 10%....we never have and unless it was extraordinary service I would have thought that more than 10% is unnecessary....tipping is still not as much part of our culture as the USA ...you would always tip a hairdresser or taxidriver and probably someone who takes your luggage to your room .... I usually leave a few pounds for the room too when I leave

D'a ken far 'is cam fae, bit, as a British citizen, I would agree.

The first bit translated from Doric to English means "I don't know where this came from, but"

I must be in a funny mood today

It seems to me that you have left the door open for a tip of greater than what you say is "the usual" 10% by including the possibility of tipping more for "extraordinary service."

It seems to me that "extraordinary service" to one person can be "ordinary service" to someone else so I guess there never will be any truly hard and fast guidelines and I'm not sure there even should be.

In hotels, I ask "Do you have a staff box?" and leave a tip of 10% when I leave.

Many British restaurants have staff boxes at their pay desks.
Tipping at the table is far less common.

>>>>
Many British restaurants have staff boxes at their pay desks.
Tipping at the table is far less common.
>>>>

i think the last time i saw a "staff box" was about a year ago at an asian restaurant in hoxton. most tipping in the UK is done as it is everywhere else in the world...left on the table, handed to the waitress, or as most common, just left in the bill's folder.

i'm not even quite sure what the "pay desk" is as most bills are settled at the table (as everywhere).

as for the 10% question, in the UK, it seems that tipping norms are far from standardised across the population. some will leave nothing or close to it and some will leave 15%+. there is little attempt by most waiters to "correct" tipping behaviours that might be below a certain level, so people just carry on with what they are used to doing.