I haven't flown BA from LGW recently, but have flown BA LHR to ARN and back a lot in recent months. Always very good service, friendly helpful CC, early on practically on time arrivals as a norm - just what one expects.
Add to that, the security at Arlanda Terminal 2, who are unfailingly pleasant, polite and efficient make the business trip almost a pleasure. Just a pity the Finnair lounge is a bit basic, compared with the usual BA ones, and the special meals menus need changing occasionally!