In relation to that Southampton-Shrewsbury game they've said it has to be played before the 4th Round, which starts on the 23rd of January. If that applies to our tie too, which it presumably does, In the meantime there are the following fixtures involving the two clubs:
13/01 AVFC v Spurs
16/01 AVFC v Everton
17/01 LFC v Man U
20/01 Man City v AVFC
21/01 LFC v Burnley