Unless the brit has that other units sitting right next to the bofors(which is completely against the only singular reason to ever build it, you know, so your units can be somewhere else), you should be fine.
Alternatively, without investing into LEIG, you can just take a pair of volks and "feed" them to bofors once puppchens are in place, it'll be down before you'll lose more then a couple of models, unless for whatever reason you have chosen to approach it on red cover(this is how I did it).
So you mean u have your whole army at the bofors, while the brit sit there and drink his tea and look how u bring down his emplacement? Long time ago that u play this game, right?
Its almost this real situation:
brit build a bofors, sit his army in the near from it...and can expand from this point, whenn u try to deny this..he can backpaddle behind is Atlantic-wall and is safe. even p4 and panthers struggle, while at this point there are handheld AT, AT guns and tanks on the field from the brit player.
so there is not this moment, you can: Oh i smoke this shit and kick it away