good buy,,, i have found in my experience ( and i used to sell cars for arnold clark as well ) that the selling garages so called service isnt worth a sh*t.
they rarely change the plugs
they put crap oil in
and they just skim the rest
anything to keep the costs down.
i bought my car around 4 months ago and they serviced it before the sale marking on the service book that plugs etc had been changed, it also had 8 months mot.
the first thing i did was re-mot it ( best way to check for any defects and only £50 or so )
the mot was clean.
around a month ago i had it serviced and the spark plugs have been in there for years lol ( i knew it )
got a complete oil change ( plugs and oil supplied by me )
changed all the filters
engine flush
and brake fluid change.
tbh it doesnt drive any different as its only 4 years old but at least i have piece of mind the correct stuff is in the car now.
as for your whistling brakes !!!
cant recall ever hearing a whistle before but one possibility could be the surface rust on the brake discs just gently hitting the brake pad as the wheel is rotating,,, if it is it will dissappear in a few days.
may be something completely different but brakes do not like sitting around,
keep us posted buddy