The first definite mention of cricket in connection with the county is a highly controversial match in 1724 between Chingford and Mr Edward Stead's XI, which is recorded in The Dawn of Cricket by H T Waghorn.
In Dawn of Cricket, H T Waghorn records a pre-announcement that a "fives" game involving a Hambledon side would be played on Sat 28 August at the Artillery Ground.
H. T. Waghorn, The Dawn of Cricket, Electric Press, 1906.
The Dawn of Cricket (1906)
Waghorn, H.T. (WDC): The Dawn of Cricket.
The earliest known match in Middlesex took place at Lamb's Conduit Field in Holborn on 3 July 1707 involving teams from London and Croydon (see The Dawn of Cricket by H T Waghorn).
The Dawn of Cricket by H T Waghorn (WDC)
Beldham's first match in Scores & Biographies was for All-England v WCC at Lord's in 1787; but he was previously recorded as playing for Berkshire against Essex in 1785 (this match was reported by H T Waghorn in his Dawn of Cricket).
It is no overstatement to say that the opening of Lord's and the foundation of (or reorganisation of the gentlemen's club as) MCC in 1787 ended what H T Waghorn called The Dawn of Cricket.