Ben has taken the time to photograph the comparisons in different ways, as you can see here:
Earlier he posted a similar comparison, but this time showing the Italeri figures with a sample from Irregular’s 20mm range. His post is here:
The plastic figures are found in Italeri box 6094 “British Light Cavalry 1815.” According to PSR, this set was released in 2008, and includes 17 riders in 7 poses, as well as 17 horses in five poses.
In the images above, Ben compares a 25/28mm Irregular figure (top) and a 20mm Irregular figure (bottom) with an Italeri rider from box 6094.