Hi, I am not sure if you are aware but there is a board dedicated to UK visitors if you would like to post there.
However, as another UK resident and regular visitor to WDW, I can certainly give you my input. We do tip housekeeping (Mousekeeping), normally a couple of $$ per day (have read that some people leave $1 per person per day) as there are generally only two or three of us and we are really not messy - in fact, I generally make the beds int eh morning before I leave the room. We are
DVC owners so, when we stay in DVC accommodation, we tip more for a full clean than trash/towel replacement. However, you do not have to tip for mousekeeping, as it is not considered a tipped position at Disney. That isn't to say that you can't tip if you wish.
As far as restaurants are concerned, you are technically tipping for service (the norm is 15-20% for table service; some people tip less at buffets). However, if the food is sub-par I would not have a word with my server (or a manager if the server couldn't help). Depending how the server dealt with any issues, I might adjust the tip, but I wouldn't generally stiff the server over food quality.
You only tip at table service, however Wolfgang Puck Express at Disney Springs is classed as Quick Service but they bring your food out to you and usually offer to get anything else you might need. We normally leave a few $$ there - the food is really good too.