for their usual application they are found in the decree associated with probate or intestate decrees (just look at any wills etc involving under age children); but yours derives from a decree of the civil criminal courts thus any surviving records would presumably be there, all such records for this period are held by Manx Museum but I've never researched such - I don't know how many cases similar to yours exist but I suspect very few so I suspect some informal arrangement - have you researched the actual guardian - was he a landowner,sumner or just a possible friend of the family