Have I missed anyone posting the cost of this fast track service @ BKK ?

To be honest, my worst wait there has been about 30 minutes so far, so considering the bags will not be there for most of that, I wouldn't be prepared to pay much.

As for Heathrow, on most of the recent return trips to T2, I've had no queue and have gone through in about 30 seconds. Makes me proud to be British. At least until I get to the slow baggage handling service (where they don't even get the priority Premium Economy luggage out first).