Generally I found the to be a miserable trio, not helpful unless it suits them I assume?
I used them twice recently as I gave them the benefit of the doubt after an initial poor service experience however this was replicated on the second visit so no more visits from me; not that I imagine they care as I assume (again!) that they don't base their business model on repeat custom! I imagine (had enough of assumptions moved to imagining now) they must know something about plumbing but either they want to keep it to themselves as knowledge can be power or they are incapable of articulating it to us mere mortals!