Large sturdy cardboard box (Malvern Link WR14)

Hi I am looking for a large and sturdy cardboard box to send a Hoover in, needs to be a minish size of 50x50x40 cm. - perhaps someone had bought a printer or a small lawnmower or equivalent and it came in a box? If it's a lot larger than my size above no problem I can cut it down. Main criteria (besides size) is that it must be a good thick cardboard. Many thanks