Missing episodes????

I'm watching in the UK on Universal. Has my SKY box missed a couple of episodes? I set the whole series up to record and have not got the finale of season 4, and ep 5 of season 5 is also AWOL? I have tried to find them on "on demand" but to no avail. Anyone else experienced this and any ideas where I can get them (without paying any more, my SKY subscription is expensive as it is). Cheers.