As a Select member he must issue at least a "Minor Works Certificate" although fitting the RCD spur at the board could be deemed a new circuit in which case an "Electrical Installation Certificate" would be required.
Building control would only have an input if the bathroom alterations were subject to planning permission/building warrant in which case a "Scottish Building Standards Certificate" would be required.
You could contact Select but they are not really interested in financial disputes. If you feel the work is not up to standard you could ask Select to carry out an inspection.(free if they agree with you but chargeable if they find in the contractors favour). From the photographs i have seen the workmanship looks OK some labels missing from board is all I can see wrong.
I would agree with most that it is expensive, in Glasgow I would be £300-350 (including labour no more than 2 hours first visit and 5 hours to fit out and test.)