You’d need to be more specific about what you want if you don’t intend to learn to CAD up the model yourself or can’t find one on thingiverse or elsewhere on the net. For getting printing itself done you can check out 3dhubs or let everyone know what country/region you’re in to see if it makes sense to print it there and ship to you money wise.
Regarding specifications, saying a little bit bigger isn’t super specific would be nice to know:
How much extra space is needed for wires?
Where do you want the wire ‘ports/holes’ to be (how big do they need to be)?
Do you want to re-use the existing screws that hold it together to hold its enclosure or just going to glue it closed or want separate screw holes?
Does it need to fit the curve of a board at all, if so which way will it be oriented? (images of the concave of the deck would help if it has a substantial curve to it)