[[WMG:Steve is currently the head writer of ''InspectorSpacetime''.]]
Given that Steve Taylor is a thinly veiled version of Creator/StevenMoffat, and that we know from the Moff's epilogue that he was writing for a show that was clearly a fictional version of ''Series/DoctorWho'', this makes perfect sense.
Hear me out here. ''Coupling'' ended in June of 2004. The first episode of the new ''Doctor Who'' aired in March of 2005. While that is a sizeable gap, a show the size and scope of ''Doctor Who'' probably requires months of planning and pre-production (according to that other wiki, the episode "Rose" was produced and filmed in July and August 2004.) Now, look back at Series 4 of ''Coupling.'' Oliver's bookshop with the life-size Dalek and his "Bring Back Doctor Who" were obvious enough, but there's also a lot of [=TARDIS=] blue floating around (the clipboards at the antenatal class and Susan and Steve's refrigerator, for starters.) Moffatt had probably been brought into the ''Who'' loop months earlier since he had to write "The Empty Child/The Doctor Dances," which probably overlapped with the production of the last series of ''Coupling.'' Moffatt knew that ''Doctor Who'' was coming back, and, epic TrollingCreator he is, peppered all of Series Four with clues.
* Plausible. I would even say confirmed, but I don't wanna speak for anyone else.