I have some of the UK issue DVDs of Space : 1999 - 4 volumes of season one - each with 4 episodes plus various extras (including an advert for a Space : 1999 ice lolly!).
Even though my earliest memories of Space : 1999 were of watching re-runs of season 2 in the late '70s (one episode of which put me off eating 'Cornish pasties' for many years!), I seem to enjoy season 1 a lot more... not that season 2 isn't that bad either.
All the best,
Ian W359