As I am reading and taking notes from the book Inverurie and the Earldom of the Garioch, I found a short section about this battle which is also known as the Battle of Barra or the Battle of Old Meldrum.
This battle occurred as part of a civil war between Scottish leaders and preceded the wider war for independence. Robert the Bruce met John Comyn, Third Earl of Buchan in the battle. The battle was fought in May 1308, while some sources say it was fought near Christmas 1307. In the previous year, Robert the Bruce killed John III Comyn, know as Red Comyn. He was the nephew of the former king, John Balliol. It was a decisive battle for Robert the Bruce and it gave him control of the north. Likewise, victory over Comyn solidified his position as leader of the Scots.
The battle of Inverurie was fought near the present Castle of Barra, in Bourtie parish, about two miles south of Oldmeldrum. https://en.wikipedia.org/wiki/Barra_Castle
I refer the reader to go to pages 47-50 in the book for a more detailed account.
In the text there is no mention of the Leslie involvement in the battle. This could be a worthy area of research.
You may read more about this at:
https://en.wikipedia.org/wiki/Battle_of_Inverurie_(1308)
There is also a blog post located at:
https://doriccolumns.wordpress.com/battles-in-aberdeenshire/battle-of-barra/