So kids can't technically go in any shop? It's probably better they are hanging at Arfa's than round the back with a bottle of vodka..
Ie back to the shop. NT
Not easily service by a DIYer and costly to have a pro shop repair it.
Try using a shop vac on it. See if it gurgles when you flush a toilet if you think the vent is clogged or non existant.
Company named Pittman near me makes them. www.pittmannet.com Also Google 'small motors" Lots of import & hobby shop should have them.
They are called "basin wrenches" and for the price of a plumber you probably can buy about a dozen of them (depending on where you shop)
Our local rental shop has a whole rack of hole saws. Or is that a hole wrack of whole saws? Anyway, they are available to rent.
Easiest way I've found is to make the corner section in the shop and then field-fit rather than try to fit the miter itself onsite....
Just go to Ebay and you can find any quantity batteries that you want, from 1 to 100 at prices far below the local retail shop.
According to the owner of a local supply shop, all washered faucets leave the factory with flat washers. Most plumbers replace bad washers with flat. Colbyt