Based on the above discussion, I've put together something a bit more visually comprehensive... Provisionally numbered '208' for simplicity, the route is shown on the map below (hopefully it'll work):
http://goo.gl/maps/JzR0g
Service 208 is based to change in-line with the completion of the works in Sunderland. Commencing on Fawcett Street at the bus stop previously used by service 20 (outside of the former Primark building), the service runs via High Street West, Bedford Street and St. Mary's Way. A new bus stop has been created on St. Mary's Way, and this will allow links to local shops such as Argos and Marks & Spencers, as well as the Sunderland Empire. After calling at St. Mary's Way, the service runs up Silksworth Row, before proceeding via the usual route of services 8/20 to Bishopwearmouth Cemetery. From here, the service runs via Hadleigh Road, Helmsdale Road and Holborn Road (as per the current 8 route), continuing the usual route of services 8/20 to St. Anne's Primary School. From here, service 208 runs via Hylton Road and Prestbury Road (as per the current 20 route), returning to St. Anne's, and then turning into South Hylton. The service then continues the current 8 route to Claxheugh Road.
On the return journey from Claxheugh Road, service 208 runs direct up Hylton Bank, opposed to calling at the estate in South Hylton as per journey to Claxheugh Road (similar to the final 8 journey of the day to City Centre). The "Hail & Ride" style service used in this estate can be used in conjunction with the 10 minute frequency to compensate for the lack of a journey via the estate in this direction. From here, the service continues via route taken to South Hylton. At Silksworth Row, the service continues via St. Michael's Way, Albion Place, Holmeside, before reaching the terminus of Fawcett Street.
The PVR would be seven (service 8's PVR of 2 plus service 20's PVR of 5). Provisional times given on the PDF document below, loosely based on current timings of services 8/20...
The journey time of the current service 20 (City Centre to Prestbury Road) increases by 3 minutes, while the return journey (Prestbury Road to City Centre) does significantly increase (40 minutes opposed to current 19 - I did indeed underestimate the timings), though users from Prestbury Rd are in the minority, and those within walking distance of St. Anne's could easily avoid the extra journey time.
11 minutes layover time in total with service 208, compared to the current 10 minutes which service 20 has and 4 minutes which service 8 has - timings are also actually quite loose, so reliability should be less of an issue.
Thoughts/opinions?