Well having just left there,I can confirm the delays are due to London Heathrows w/x problems today.One flight for example the BD93 due operational reason was delayed 3hrs 25mins!!
As for the stands there are 2 stands capable of taking the A321,these being 4+5.Aswell as stand 6 being able to accommodate an A320.With regards to the late flights tonight there are only 2 A321's due with another A320.The two A321's being G-MIDH AND G-MIDJ(nightstopping when it arrives at midnight)The A320 operating is G-MIDU.Also they are not ALL arriving at the same time!!
Regards