Hotel Tango, 2hrs + connecting time with hand luggage only at Stansted, is in my mind and that of others, quite sufficient !
Obviously not as it turns out! Two hours is more than sufficient if all goes according to plan. There is however no guarantee that that will be the case. You have to make a risk assessment. Go with the 2 hours and if it fails, accept the consequences or go for an extra buffer (which still won't guarantee anything)! No matter how punctual an airline is generally, none is ever 100% punctual. Sh*t happens and flights get delayed. For me the bottom line is that you took a gamble and on this occasion it didn't come off. Accept it and move on.