The RA uniform was similar for all the Royal Artillery, Dark blue with Red Trim, although RHA units tended to wear Hussar style uniforms, as shown in some of the pictures. RFA and RGA (slightly later than Henry's period but a good dividing point tended to wear foot artillery uniforms, that is to say a Shako or helmet. Having said that the foot artillery did adopt a busby during the period in question. I would recommend you try and get hold of a book entitled Dress of the Royal Artillery by Campbell. If possible go for the 1966 edition as this was the updated one, although the earlier edition will cover your period very adequately. Badges tended to be the same, even during WW1 the cap badge was still identical, indeed even today all Regiments wear the same cap badge, it is only when wearing the sidecap or beret that the RHA wear their cipher and that wasn’t introduced until the 1930’s so it doesn’t enter into the equation.