Grooming long haired guinea pigs best brush?

[MillyMollyMardy]

We have 2 long haired guinea pigs (they were short haired when I bought them) I wouldn't have got them if I'd realised. They are now about a year old and I've just given them a trim for summer.
Despite regular grooming they both seem to have lots of skin flakes in the deeper hair that wasn't visible whilst it was long. It's not mange it just looks like skin that's trapped and their skin looks healthy.
Can anyone recommend a brush that would be better, are furminators suitable for gps? Currently using a soft grooming brush.

I accidently bought a jet black Peruvian (Marmite) when I was in my 20s (lovely animal but I wouldn't have chosen a long haired. She looked like a regular piglet)

Her fur was glossy and sleek, but I kept it floor length and shorter round her rump.

Have you given them a bath?
Maybe treat them to some Gorgeous Guinea Melts (like a pre treatment, melt in hot water, cool and scoop it over them before shamppoing) then comb through.
I used to use a baby comb on Marmite (non scratchy, short prongs)

I looked on a Furminator website (I think USA) , I've seen them on QVCuk.
They recommend for small animals -rabbits and ferrets to prevent hairballs. Not sure if my pigs would tolerate it.

I can't even work out what breed/cross they might be they're tufted with long wiry hair so don't groom easily. The closest seems to be sheba mini yaks with added fuzz.
They look at little more maneagable after their trims.
I haven't bathed them, I'll look for the guinea melts.
One of them is very vocal so I'll look forward to the noisy complaints.

Awww @ mini yaks with added fuzz

I have now tried the furminator on them both. Lots of wingeing but if I stroke them and alternate with the furminator they moan slightly less. It has pulled lots of debris out and lots of loose hair as well.
We now have 2 less mini-fuzzy-yaks

Will the fuzzy-yaks appreciate the lighter coats now with this warmer weather?
Probably yes, but they won't say Thank You

Definitely no thanks from either of them, but they appear to have forgiven me and fuzzy 2 almost ate from my hand today (she is very timid and tends to hang back).