These three Walloon regiments of foot, together with a regiment of dragoons, formed part of an augmentation to the Anglo-Dutch forces operating in the Low Countries in 1703 (given commitment and resources allocated it would be more just to refer to Dutch-and-some-Anglo forces
). This augmentation of 1703 consisted of 20,000 men, the cost of maintaining them divided equally between England and the Dutch Republic.
Part of this augmentation was formed by troops raised in the prince-bishopric of Liege (i.e. three regiments of foot and one regiment of dragoons, altogether about 3,000 men. Liege was then a state within the Holy Roman Empire, and not part of the Spanish-Netherlands). The remainder was formed by regiments provided by a host of German princes. So, in some sources these Walloon troops are referred to as troops from Liege.
The three regiments of foot were somehow considered part of the Dutch army, as the topic started indicated, the regiment of dragoons was somehow considered part of the English army. Though England and the Dutch Republic each paid for 10,000 (i.e. half), the actual division of the troops over the English and Dutch army was not that neat: 13,500 were considered part of the English army, the remaining 6,500 were part of the Dutch army. But that had probably more to do with administration than anything else.
The fate is the regiment of dragoons after disbandment is interesting, since the Protestant officers were granted English half-pay in 1714. This was quite unusual for a subsidy regiment, but it may be because these officers were actually Huguenots. However, I haven't checked this.