As you have said Lossie would not be able to speed up the flow as it is not the Approach service provider. Inverness works on a procedural basis with a landing interval of 10mins between ac carrying out the full procedure. So if no one goes visual and you are number 4 then expect to be flying around in a circle for 40 Mins. This compared with ac doing 180kts on final approach requiring 6nm between them for wake turb, it would take 8mins to shift the same 4 ac (figures used for simple math) using radar.