Next weekend (Thurs-Sun) I need to be in Madrid.

I've managed to grab a Business Iberia Flight Thursday on the A340 (so should be a decent seat for the short flight) - However, currently there is no availability for the return on the Sunday at all, is this normal?

Looking at this Sunday there seems to be around 10 different options available to me, should I expect for something to pop up before next week? or does anybody know why this weekend would be any different?

If it comes to the worst what would be my best option getting back to Heathrow to collect my parked car!? (have Avios/ limited cash!)