Seeking advise on replacing light switches (1-way, 2-way, 1-gang etc) (UK)
You need 


2 x 2-gang 2-way and 
1 x 1-gang 2-way


A faceplate with two switches on is two-gang.

Note that 1-gang 1-way switches are also available, slightly cheaper; this will not work in your application. 

Switches that can be wired to operate from two locations is a 2-way.

(This is UK terminology. USA terminology is different.)

http://wiki.diyfaq.org.uk/index.php/2_Way_Switching