Scooter service intervals

So my aprilia sportcity one got written off by the insurer . I am in search of new scoot and i think i am gonna go for SYM JET4 125 as thats all i can afford with a pay out.
My question is: Does services have to be done by authorised dealer or can be done by normal mechanic (want to keep the warranty).
I am asking cause service intervals on them SYM should be done every 3 months or 3000km. 4 services a year times probably 80-100 pound seems to be very expensive. Whole idea of the scooter is to keep the cost down.
Warranty on them yolks is 3 years

 

Better option: Don't buy new.
No less reliable if you get something decent and well looked after, and you'll save a heap of cash for if something does go wrong, which will more than likely out weigh the benefits of a new bike that relied on the warranty. I have a Sym, (in my pic) and the only times it's gone wrong is due to me thrashing it they're reliable and even cheaper second hand

 

Bit worried about buying second hand scooter, different story with a car (bit more knowledge about them). Plus i am living in Northern Ireland and there is not to much choice in pre-loved scooters :/

 

Trust me there's alot more that could be wrong with a car than with a scooter.
Aslong as there's no rattles from the engine and it rides fine then all should be good.