Defruiter
Will including it on the charts make a difference? Perhaps it could, I'm not so sure though. The things we need on first contact are already mentioned on the ATIS, which everyone inbound listens to. Surely, as long as the ATIS is listened to, everyone should know what we need on first contact.
In theory you are indeed correct, however the ATIS is often listened to before Top of Drop which is easily 20-30 mins before initial contact. Then you are relying on the pilot to write down what you need to hear, since an unfamiliar crew will forget what you want by the time they get handed over to Heathrow. Finally, some airlines get their crews to jot their ATIS down on a card that is roughly in the crews field of vision. However for some, it gets jotted down on the Flight Log (PLOG) and this may be clipped to a chart holder or attached to a clipboard which could be propped up anywhere within reach! It is normal instinct to glance at the ATIS letter on first contact with any approach unit but many of us won't go reading through the whole ATIS again. This is purely because we will have covered the runway and weather etc when we are briefing for the arrival. With the note about what you want on first contact being at the end of the transmission, then I would personally say that is perhaps not being placed in a obvious place for crew who are not that familiar with Heathrow.
When flying along a busy arrival route it could be said that crews will refer to a STAR chart more frequently than they need to consult any paperwork that will have the ATIS written down. Airlines tend to encourage that the admin should be wrapped up at FL100 in the descent so an efficient crew will aim to get most of the flight deck admin done by the time they contact Heathrow. That is of course in a ideal world and finishing your crew meal off in the descent will mean that you will be writing well into the descent!!!
However the STAR charts for any of the London airfields have enough extra text as it is so perhaps there might not be an ideal solution.