This mounted trumpeter of the Household Cavalry was given to me in 1960, it may not have been the very first toy soldier I ever owned but it is certainly the one that has remained in my possession the longest. It was made in England by Wendal (Wendover Aluminium), it is aluminium and is 54mm.
Aluminium figures were very popular in post-war France but never really caught on elsewhere, the only exceptions I can think of are Krolyn of Denmark who made copies of Elastolin as well as some original designs in this material and Wendal who made copies of Quiralux figures. Quiralux were the market leaders in manufacturing aluminium toy soldiers in France.
Wendal also made original figures of British subjects such as this trumpeter from a set of the full mounted band of the Household Cavalry, while there is little appetite for them amongst English collectors they are particularly sought after by the French because they offer something unusual that wasn't available in France.
Aluminium figures are made by slush casting, a process whereby the master model is pressed into compacted damp sand, then removed and the molten aluminium is poured into the resulting cavity. To make a two part mould the sand is packed into two steel trays which are then "sandwiched" around the master model. When I was at school we used to do slush casting in metalwork lessons, no health and safety worries back then!
The limitations of this casting process means that aluminium toy soldiers tend to be less animated and detailed than those made in other mediums, although very robust the material is also brittle and will break but is easily repaired with superglue. When they are stored loosely in a box they will tend to loose virtually all of their paint which has led to a trend among modern collectors to repaint them and I have to admit the results are usually a big improvement,