The Throtle Bodies need balancing every 10Kkm/6Kml.. Not only because the service manual said. If you stay beside your mechanic when is servicing your triple you'll see by your own eyes the difference at the flow in each cylinder. They are OK only when they are going equal. For best results is needed exhaust-gas analyzation at the same time.
If i was you i would go at the Spa with the higher cost but more responsible behaviour.
From my experience, after 10K km the equal settings are lost. For example one TB runs leaner when the others runs reacher, each in different level.. That happened because of engines vibrations and that's why Yamaha "tics the box" in service/repair manual. Then your bike runs better and faster than before. After use the bike starts again to loose the "equality" until next service
Every 12K miles it needs and spark plug change too, but in your case they are staying there for more than 2,5 years... and for how long? When you spent lots of money in mods it's a pitty to leave the bike in old sparks or brake fluid for long periods.
Brake fluid MUST change at least every 2 years.
Fork oil in our bikes is better to change once a year.
So there are many things to be done.... Ask Spa about..
Hope this helps mate!
180 pounds only for oil change is a lot of money