He was at the tournament for the pool matches. I've seen on youtube matches, including England v Australia, England v Japan, Wales v Ireland, and Nigel Starmer Smith commentated on them all. If anyone was there on BBC radio 2, most likely it would've been Ian Robertson and Alastair Hignell.
Here are Radio 2 broadcasting Ireland, Scotland and England matches in the group stage - a bit of duplication as they spanned two issues.
As you can see, Ian Robertson did the England matches and it looks like the regular commentators from Radios Scotland, Wales and Ulster commentated on their games. They wouldn't have covered anything but the home nations in the group stage. I like how despite matches kicking off at 2am, 4am and 6am, they didn't offer continuous coverage and opted back into the main Radio 2 output for half an hour between them.
Were the pool matches shown live on the BBC, or was the highlights shown on a Rugby Special type of programme?
As I mentioned on the previous page, only three matches were shown live on the BBC, one quarter final, one semi-final and the final, all the others were either at 2am which was presumably considered a waste of time to broadcast or clashed with immovable Breakfast Time or Open University programmes.
As I say, the England games, which were pretty much all on a weekend, had full reruns on Grandstand and there were highlights shows most evenings with Steve Rider in London. On Saturdays, these were part of Sport Special - https://genome.ch.bbc.co.uk/schedules/bbcone/london/1987-05-30#at-22.45
- which ran most Saturdays that summer.
As you can see, the Beeb's commentators for that tournament were Bill McLaren, Nigel Starmer-Smith and Fred Cogley who was usually on RTE. I think he might have been the primitive "world feed".