We read about 30 year leases do they allow 99 year leases as in some parts of Australia?

nope, 30 years is the max, not sure about the legality of multiples of 30 years though, i know on a 3 plus 3 lease they can still kick you out unless in a court of law you can prove major upgrades to the building..

While looking for condos, I found some leasehold places that had a total of 55 years (30+17+8). Still a long from 999 year leases in the UK.

30 years is the max. If you get a longer one it will considered as 30 years.

If you have options to extend, read it like it is an option for the owner, not you. Sad, but really true.