Sector 29 was the Mancunian equivalent of London Middle sector (25/26) and ended up at Prestwick ACC.
I've dusted off my New EnRoute Centre (NERC) Outline Operational Plan (OOP) from 1991 and this is how we visualised the sectors then
So in 1991, the sector design had Sector 30 as a north/south easterly sector over Manchester with Sector 29 as the westerly. And sector 31 as a low level Wirral sector under sector 7.
The 'live' NATS operation subsequently redesigned North Sea and Lakes/Wirral and to help with the transition to Swanwick (staffing) as well as providing more capacity/less delay, as much airspace as was possible was transferred from Area to Terminal at West Drayton, Manchester and Scottish. Looking back, getting Swanwick from a concept to operational reality 10 years on from hand-drawn sector ideas seems a minor miracle given the scale of the change (new site, new operating procedures, simulating and training the new airspace, new equipment etc).