The actual answer(not the sarcastic one from my next door neighbour!) is about 6 to 10 feet, depending how friendly they are !!
The same is true for 124.5 and 126.3. HOWEVER, the person on 124.5 (Tay Sector) is often working FIR traffic on a RIS, co-ordinating with Buchan/Neatishead etc, so is quite busy, along with W3D and P600 traffic.
It's often the case that someone gets airborne from Edinburgh and before he or she has the flight progress strip the TALLA (126.3)controller is asking for the inbound on one particular side of L602.
There is also the consideration of D512, which the MONTROSE (134.77) controller has often forgotten about as it's not in the UIR, and the TAY controller then has to position the ins and outs to best avoid this especially when it's active to 20,000 feet.
There are some of the reasons why you have the hard task of selecting heading mode once again !
I hope that provides something of an answer, but if you need anything more please ask, or even better come and have a visit !