Unknown British (???) webbing pouch

[DavK]

I recently picked up a job lot (mostly P58 and PLCE webbing parts), which included this unknown pouch. The overall style is like a mixture of P37 and P58, but its neither of those. The top (or is it bottom?) has two separate closing flaps, with an opening between them. The dimensions are 21x15x6 cm, so its too thick for an entrenching tool. My guess is a water bottle or maybe a smaller radio. There are no markings. The pouch can be attached to a P37 belt, and the style is similar to british equipment, so I guess it may be british (or commonwealth), but dont know anything for sure.
Any help is appreciated!

[sgb19]

a bit late, but since no one responded... Bulgarian shovel pouch for their P58 style webbing. First introduced for paratroopers in 80s, later to other units in 90s. Most units were not issued the new folding shovels for this pouch, so sometimes used for the water bottle.