I'll start you off
Lighting
Heating
The issue Andy is that most people will happily pay a fare price for a good job.
Its the latter that is the issue, having spent time in and out of dealerships (many Marques) in front and behind the counter for most of my life, the quality, commitment and general knowledge of the spanner holders is very poor.
I can honestly say that not once have I had a job completed by a dealership where the ouput was upto the standard of that which left the production line.
Which for me, is a big issue that the whole industry should be looking to address. However, as you are aware, in a world where the many stay is owned and operated by a few very large organisations and holding groups where the main stay of the business is from places other than the aftersales as a whole and whilst the quality of what falls out of college remains at its current hopeless level, there is little hope.
Hence, customers with any level of motoring knowledge will not be satisfied with under performing outfits.
I proposed a bonus scheme some years ago where the only bonus payment made would be based on zero returns over a 1 month period........no time based bonuses plus checking of all jobs by the foreman.