I reckon 100g meat is normal and 200g for an adult is AMPLE, especially given all the additional stuff you get with Christmas dinner. That quantity of meat should be more than enough for two days. (But all depends how greedy you all are).
Thank you - yes you are right, that should be enough. None of us will want a massive portion. I'm just getting some pre-Christmas twitchiness. Although we've only got one extra person to feed, I don't want there to be any "holding back" if it looks as though there won't be quite enough food. But I also don't want there to be tonnes left over.