UK Fiesta Rear Speaker Wiring

We've got a '99 Fiesta Zetec with no rear shelf speakers. The dealer tells me that it should be fitted with the rear speaker wiring as standard (and
indeed the wires are present at the head unit).
The dealer says the wires will be taped in to the loom and will take a some finding - so before I go removing trim etc, does anybody have any pointers as to where the ends are likely to be.
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