On the SYW Journal, vol. VIII, 2 and 3, there is the Peter Lenders article on the Dutch Army in WAS which gives the following info:
1747 campaign: 3 Hessian btns (each of 10 coys)
1748, camp at Waalwijk 9 Hessen-Kassel btns, 5 H-K sqdns, 18 arty.
at Rocour:
Hessian Mansbach battalion
Hessian Regiment Donop
Hessian Regiment Garde
Hessian Regiment Prinz Frederich
Hessian Regiment Grenadiere
Hessian Regiment Prinz Max
Hessian Cavalry regiment Leib
Hessian Cavalry regiment Graffendorf
Hessian Cavalry regiment Isemburg
Hessian Cavalry regiment Prinz Max
The source is Austrian General Staff history of WAS ( something like "Osterreische Erbfolgekriege
we could look at Google). There is a breakdown of single lines/wings with the battalion subtotals which shows how the "regiments" where indeed 1 battalion strong.
Present a Lawfeld:
Hessian Regiment Garde
Hessian Regiment Prinz Georg
Hessian Regiment Konig
Hessian Regiment Prinz Max
Hessian Regiment Isemburg
Hessian Regiment Baumbach
Hessian Cavalry regiment Leib
Hessian Cavalry regiment Graffendorf
Hessian Cavalry regiment Isemburg
Hessian Cavalry regiment Prinz Max
The number of Hessian battalion is not given: however there are 16 Hannoverian and 14 English battalions and some aritmethics on the total strenght gives 6 Hessian battalion. The average strenght is estimated in 600 men.
I will go with Christian hypothesis. I'll try to search more.