Any question answered...

Not sure the expedition ones have the interval training timer. The Ebay one only has a 10 lap memory. Are you using it for running? Mine has a 100 lap memory. Once you start using the memory, you fill it pretty quickly.

30 is a nice minimum.
http://burasi.co.uk/index.php?i=B000JNJLXA

I'm also a fan of velcro straps. Hate having a watch too tight or too loose when running.
http://compare.ebay.co.uk/like/271141296455?var=lv&ltyp=AllFixedPriceItemTypes&var=sbar&cbt=y

These are quite good Gymboss Interval Timer & Stopwatch GB2010 BLACK: Amazon.co.uk: Electronics

Cheers.

I mainly want to use it for skipping. 2mins skipping, 1 mins of press-ups/similar. Maybe also some running.

I never really considered how many I'd need. If you wanted 2min, 1min, 2min, 1min, etc. would you just need two and reset?