Just had a look at my last three Plus 4 services by a local independent garage
Service as necessary inc oil/air filers 5.5 ltr fully synth oil screen wash etc
Total inc vat
2020 £160
2019 £150
2018 £140
Price is going up - will have to watch it!
Couple of years ago they fitted a new coil pack + ignition lead set + spark plugs - Total £198
Prior to that I used IK Classics - they charged about £350 for a service.
Service looks cheap but car runs okay and is reliable.
Never failed an MOT - they charge £25
Keeping the Plus 4 is cheap as chips really - tax and insurance about £500 or £600 for both
You know it makes sense! 
