I am experiencing slow drainage of water from my bath and a foul smell when I run the taps in my bathroom. I am assuming I have some kind of partial blockage in my drains. I was considering using a product called One Stop Drain Cleaner and wondered whether anyone could advise if this is a reasonable solution? If so, is it poured down the plugholes or should it go into the (open) drain outside (this drain sits underneath my bathroom window and it drains my bathwater etc. There has been toilet roll spewing out of it recently).
the toilet roll is probably the issue as this should not be in the drain but if the blockage is further up the pipe then pouring down the drain will not help.
I would try caustic soda and poor down the sink and bath plug holes and see if that clears it.
Failing that, pour water down the drain and see if that clears, if not then the blockage is further down. Try caustic soda directly down the drain.
Yeah, whatever you do, ordinary shop bought stuff is as good as useless.
Try a plumbers merchants and get acid called one shot (or similar stuff). It's reasonably cheap and it does the job, especially if it's paper, fat or pooh.
If you're getting sewerage backing up to your drain you need to get the drain cleared - you have a blockage. Caustic may help - note though if you put it down your sink it may well destroy your plughole chrome. I had this and needed to get rods to unblock the clog.
Wilkinsons or other hardware places should carry caustic soda. Get the granulated stuff with no brand name for the best deal. I recently chucked three tubs down my outside sewer cover and think I got lucky that it worked.
For sinks you only need a little because there is not much liquid between the plug and the trap or bend. Blocked sewer pipes contain many gallons of water so rodding is best, but a nasty job.
I agree with Whickerman - seems you may have a blocked sewer - look inthe manhole if you dare! Beware of paying drain clearing companies though - you can probably get a sewer unblocked for free by your water company (but not pi pework in your house)