but that is now true, apart from nominet domans you can renew all domains for 10 year, some for longer.
Perhaps its you hosting company that limits the number of years to two, I did that at my hosting company too, its mainly for fraud prevention

I have norminet domains and one info domain. A friend who works closely with Norminet mentioned that they were going to change the limit soon.

Nomiment changing domain registration limit will be greate, at the moment, its a maximum of 2 years