The decision to buy the XLA woulld be made by The Thomas Cook Group and not TCX. TC plc are on a spending spree but i doubt very much that the XL Group would be on there radar, although stranger things have happened.
XL have a french airline which may be of interest for capacity for the French tour ops of TC. Travel City Direct and Kosmar holidays also may be of use plus the Australian business would give TC a foot back into Australia. We will wait an see.