I'm still trying to work out how "vectors to somewhere on the base turn" and "continue the procedure" is a permitted procedure. Procedural approach or vectors to final. There is no middle ground.
Here's the PANS-ATM version
8.9.4 Vectoring to pilot-interpreted final approach aid
8.9.4.1 An aircraft vectored to intercept a pilotinterpreted
final approach aid shall be instructed to report
when established on the final approach track. Clearance for the
approach should be issued prior to when the aircraft reports
established, unless circumstances preclude the issuance of the
clearance at such time. Radar vectoring will normally terminate
at the time the aircraft leaves the last assigned heading to
intercept the final approach track.
I can't find any MATS reference that permits vectoring to terminate other than on the intercept to the final approach track.