L9 Cpt-wotan
The area around MALBY can get busy with Bristol, Brize and Lyneham using it for SID and STARS around the FL70-80 levels. So FL90 eastbound from WOTAN technically subject to traffic you would be above their SIDS/STARS ie: Bristol inbounds need to be at FL80 AT POMAX, Lyneham SIDs FL70 at MALBY and Brize similiar. Of course this is also subject to Sector 23 traffic and not to mention CAS leavers/joiners from Gloucester and Kemble. Co-ordination outside the published procedures are subject to traffic levels and controllers workload, Bristol ATC i know had a few aircraft on yesterday avoiding weather so maybe they were busy, they are always helpful.
Hope this helps answer your question.
NM