Have look at installation manual and you'll see diagram how to connect 3ph cooker to one phase supply, or it would be at the back lid of cooker connection.
Try that http://www.tlc-direct.co.uk/Products/FB4135.html for switches and
that http://www.tlc-direct.co.uk/Products/FB4235.html for sockets.
Hope it'll helps
I was presented with an underfloor heating system which was installed by the tiler.
This installation can't be certified by tiler.
Electrical underfloor heating system is under part P building regulations.