Try ETA, they do a push on / pull off, but from memory they are larger, they also do a 110 seieries, which is 19 mm square, and push / push off. Airpac do some push on / pull off, ETA also do a rocker switch type, think Carlingswitch have some in there range, Hawco list a cheap rocker switch circuit breaker, stock one type, but not the other.
They are not that cheap, around £8 each, except Hawco ones.
I am not sure of the price at RS but I would take a look at a US company called digikey www.digikey.com I researched this subject sometime ago for my own use. They are normally very good - I use them for small quanitity prototype work for my business and you can use a local 0800 number.