I have just had my 24000 mile service done at Allan Jefferies, 27500 on clock.
The total cost £220.00 due to me pre paying £40 for the next four oil changes.
For the money they did the following.
Plug change,
Air Filter change,
Oil and filter change,
Check valves,
Replace rocker cover gasket,
Good checkover
Checked & reset the OBC but at my request did not alter the programme, Im still running on the mid 2009 setting which I prefer.
With oil the cost would have been in the region of £245