British Dispatch Rider's Helmet. The British No.3 Mk.I Dispatch Riders' Helmet was originally introduced in October 1942. The helmet is complete with its original liner, the helmet retains almost all of its original paint. The liner is in very good condition and is nicely maker marked with 'BMB' and dated 1943, size 6¾. The helmet shows only minor traces of years of storage, overall a very nice original British Dispatch Rider's Helmet in very good, mint and unissued, condition!