 At Frezenberg, they went into action in the trenches on 12 May as dismounted infantry, numbering 291 all ranks, alongside the 1st Life Guards (left in line) and 2nd Life Guards (middle in line).The Leicestershire Yeomanry (right in line), B and C Squadrons took up forward positions in the advanced trenches, with A Squadron to the rear in support trenches (approx 350 yards behind and positioned to the left side of the forward squadrons' trenches).The regiment suffered heavy shellfire through the morning, though with light casualties, until around 6am, the German infantry opposite launched an attack, which was quickly repulsed; shelling resumed until about 7