Here in the US, you might be able to find a good inspector via the NRVIA "Find an inspector" website:
https://nrvia.org/locate/
I've not used one of these folks yet, so buyer beware - you'll probably want to assess the inspector's experience and skill level, hopefully via references, before hiring one.
Regarding agents, no. You are your own best agent. Use resources like RV Trader, local dealers, etc. to find RV's in which you're interested, go take a look at them, and if you find one you like, proceed from there.
Oh, and super-important: beware of scams. The demand is so high for Class B RV's that it's prime territory for getting scammed. RVs in transport, RVs they can't show you, RVs priced ridiculously low, and on and on. Make sure you put your hands and eyes on any RV, test drive it, and look it over carefully before you start negotiating prices or handing out money.