Help building "Thomas"

I have a student who is making as a project a "Thomas" the tank engine prototype toy. He is basing the shape around the Hornby 0-6-0 "OO" gauge Thomas. he has doubled the size and wants to find a supplier of

I took some measurements and the size is :- 38mm diameter front face of the wheel, (42mm if you include to the edge of the flange) and the width of the tread of the wheel is 7 mm.

Is this "O" gauge ? ( double the size of "00"?)

Does anyone know where He could find a supplier of wheels like this ?

- they don't have to be exactly the measurements I've given you, but "near enough as the visual appearance of the model is more important at this stage rather than strict dimensional accuracy.

also does anyone know where to get coupling rods and the pins that attach them for this model?

Ideally web based would be good so that the student could look at an online catalogue.

Thanks in advance

Ashley