2012 yzf450 idle problem

Hi all, new member here, great site very informative, Wonder if anyone has any ideas to help me out????

Basically it's my brother in laws bike that has just had a full topend rebuild.
new valves and seats
relined barrel
new piston etc

We are having trouble with setting up the idle on the throttle body, we can't seem to get the tick over high enough with the cold start/idle knob, when it's all the way in the idle isn't high enough yet if you turn it down the idle will decrease till it stalls.
because we can't adjust the tick over high enough it keeps stalling and can be difficult to start.

We are swaying towards having it plugged in as have heard you can adjust things like tick over if you do this but we are struggling to find anywhere in Essex who can do this.
the cold start knob has been thoroughly cleaned ,electrical connections checked and throttle cable checked but still no joy, it really has got us scratching our heads

We have only just bought the bike so don't really know a lot about it which is why we had the topend freshened straight away.

Is there any common things to check for this problem and should we send it somewhere to get it plugged in?
Or any recommendations where we can send the bike to get it repaired?

heeellllllllp