If you want an "eye-witness" type account of 51st HD during the campaign then "Monty's Highlanders" by Patrick Delaforce may well give some background for you.
Basically, the Germans counterattacked the flank of the Normandy bridgehead against the Paras at Breville on 10 Jun. This produced a salient that 3 battalions of 51 HD (153 Brigade) supported by the 6th Air Landing Brigade helped reduce and stabilise the front line again by 11 Jun.