Usually give a tip of 10% if the service is fine. More if the service has been exceptional (~15%), and of-course no-tip if the service was below par.
Yes
'discretionary service charges' are sneaky, but I guess maybe they're designed for group/party bookings where usually people don't tip as much compared with if they were alone, and also hotels where people don't tip as much compared with resteraunts.
If the bill has included in it a
'discretionary service charge' of 10%, and I was going to tip 10%, then of-course I do not tip as it is done for me on the bill.
If the service was exceptional and thus I want to tip 15% I add this extra 5% to the
'discretionary service charge' included on the bill.
If the service was below par and I would not be leaving a tip I would ask for the
'discretionary service charge' to be removed.
Bill came up to a little over £80.
service charge came up to around £9.00
That's about 10% then, and thus what I would to tip if the service was fine. The
'discretionary service charge' would therefore become my tip. I wouldn't ask for it to be removed, and I wouldn't add anything to it.