Small HE bombs were hand dropped in the early days of the air war and it would have made sense to have had a hand dropped practice device, for which this small bomb may have been the design*. However, it also has the circumferential groove around the body (probably close to the centre of gravity), and usually there is a small hole towards the rear of one of the fins, both of which - without getting too speculative - would facilitate mounting with a remote release.
The layout shown in the drawing posted by MINENAZ16 has similar features to the later RAF 11.5lb practice bombs - a solid nose, thin-walled back end for a pyrotechnic marker, and a simple nose-mounted striker held safe by a split pin. The structure is not really that of HE, antipersonnel, or incendiary, all of which have their own design characteristics, but it would be nice to find a drawing describing Method of Filling.
*The markings on a relic 3lb bomb in my possession a long time ago were the year 1915 and the letters W D either side of a broad arrow. I cannot recollect any other markings.
Tom.