Commuting on long haul you’d need a maximum of 5 hotels around Heathrow in a month I’d say (if you are unlucky and don’t get a single afternoon/evening start - quite a possible occurrence as I found out). Depending on your taste, with the various discounts around this will cost £300 to £400 a month. You shouldn’t need a hotel for the return, but this will depend on connections to your hometown.
BA flights are practically full everywhere, especially to the regions. Rely more on hotlines than standbys for your commute planning. On that note, as others have said, I have found staff travel to be all but useless unless you are going somewhere practically nobody else wants to go (such as Riyadh or Bahrain off the top of my head). Delete any and all hope of going to Dubai, Tokyo, Kuala Lumpur or Sydney in club. Your own “onload code” will be relatively high if you are on the booking, but there seems to be an infinite number of people on annual bookable trips who will trump you in the standing order if you are on regular standby travel. If you need to make any solid plans (which you would if on leave or commuting) then it can’t be advised.
Depending on the station, some seem to take an attitude towards staff travellers too which can dampen the mood a bit. Most are lovely and helpful though, just beware.