Right back at the start bookworm said "Bristol told me that London required me at FL90 to use the airway", which would have been AC, S23. Unfortunately (and I speak as one of them) I doubt anyone would consider the TMA min overflying level before authorising departure/issuing clearance. In fact the immediate information is not to hand on sector, unless its self-calculated.
Not-withstanding those TC factors if it fitted on S23 you'd probably have been given it and amended later if TC required. I wasn't there but most likely one of the aforementioned Lyneham departures probably got on request first. They join in a holding pattern SIREN, near MALBY, and keep circling till we can take them out. So L9 is completely blocked there.
Hopefully you would have had the option - If Lyneham on request first, no CTOT, then its first come first served and you can either wait till he's up and out of the level, or you can accept a higher level (Level by Wotan) to give clearance procedurally. This is even more likely if a trainee was on, keeping it watertight - as they are taught. Murphy's law says if we gave it to you both, both would be airborne simulteaneously and one would RT fail (I know, I know, the chances are tiny but nevertheless fail safe etc. etc.) In this scenario we would in fact be trying to help you get airborne quicker.
Probably just a case of unlucky circumstances - DL on request before you (there's plenty of DL and Brize traffic with our boys out in the Mideast).
As a side note, I've never used a LOREL2M in anger!!
WW