The first is Henry J. Elwis, who appears to have begun his career at British Animated Films, which I posted about here. There he served as producer on two of the three films from the studio that I am aware of, Kathleen "Spud" Houston's How the Motor Works (1936) and John Halas' The Music Man (1938). That is, according to Denis Gifford's filmography - the in-film credits to The Music Man do not mention Elwis; I have not seen How the Motor Works but the BFI database does list an H.J. Elwis as producer.
Gifford goes on to credit Elwis with directing the propaganda films The Clothes Moth, AKA The Behemoth (1944); It Makes you Think (1944); A Ticket's Dream (1944); Bristles and Brushes, AKA Take Care of Brushes and Bristles (1944); Bones Bones Bones (1944); More Hanky Panky (1945); Writing's Worth While (1945); Tombstone Canyon (1945; not available online as far as I can tell), Brickmakers (1946) and Watch the Fuel Watcher (1946). After these last two he seems to have vanished from animation history.
The Clothes Moth.
Technically, these films are round about on par with much of Halas & Batchelor's work from the period. Did he work with some of the same staff, I wonder? Gifford does not list any animators besides Elwis himself, so I can't tell. A Ticket's Dream is an interesting short in which the floating outline of a ticket turns into a dancing human figure, a butterfly and a bird. A stream-of-consciousness piece in the tradition of Emile Cohl, it can also be seen as prefiguring John Halas and Peter Foldes' The Magic Canvas.
The other animator I learnt about is Peter Strausfeld. According to the BFI database, Strausfeld lived from 1910 to 1980; during the war he made the films Peak Load (1943), Salvage Saves Shipping (1943), Skeleton in the Cupboard (1943), and Tim Marches Back (1944), of which a brief, poor quality clip can be seen here. After the war he worked as a designer on two live action films: George Hoellerig's 1952 Murder in the Cathedral (under the pseudonym of Peter Pendry) and Powell and Pressburger's 1955 Oh... Rosalinda!! This appears to have been the extent of his career in film.
Strausfeld's propaganda shorts are an interesting lot. Peak Load makes up for its limited animation with its inventive techniques - heavy stylisation in the vein of Larkins one moment, a cutout animated sequence with live-action smoke pouring out of an oven the next. Salvage Saves Shipping is one of many films from this period on the importance of recycling and playfully explores the sight of household scraps literally morphing into armaments - a pile of old books melt like a candle and form a mortar shell carrier, while a hot water bottle and pair of shoes become a piece of abstract art before turning into a gasmask. Skeleton in the Cupboard is reminiscent of Iwerks, necessarily stripped down but maintaining a strong illustrative style.