I've got a large cardboard box which may be of use to someone before I throw it away.
It's not the strongest box in the world but I have also got some extra cardboard which could possibly be used to reinforce if you wanted it.
The internal dimensions are:
Height 117cm
Width 58cm
Depth 27cm
In inches
Height 46"
Width 22"
Depth 10.5"
I can also provide the external dimensions if requested.
Collection from PL4 Greenbank.