I recognise that grenade. I used to own it, in fact it was me that repainted it when I was involved in re-enactment years ago.
I had something like 10 or so grenades, picked up cheaply from fairs such as Tilbury and Beltring, some had bits missing and all had little finish remaining. They were all stripped, the bodies wirebrushed and painted with shellac. The green lines were hand painted and the red X's were stamped with the X from a childs printing set found in a £1 shop using Humbrol model enamels.
The other parts were cleaned up and missing parts picked up from wherever I could find them. There was no attempt to find 'correct' makers markings. A quantity of pins and rings came off eBay from Australia if I recall correctly. As such the various parts were mixed up, but the grenades served their purpose on reenactment displays for many years. Most of them were eventually sold on specialist auctions after I gave up reenactment.
The filler plug with the wonky W D marking was in one of the grenades when purchased, but I always thought it was not real.
The body marking is J H W which I believe is John Harper, Willenhall.