I have owned the car for about 5 years but recently there is an obvious sloshing noise when turning direction and/or driving over speed bumps etc. It seems to have started around the time it had a service - including cambelt, water pump and new rear discs and pads, although the exact time the noise started I can't be sure of.

 

Do any of you wonderful people know what may have caused this noise to occur and how to remedy please?

If it were me I'd be checking the spare wheel well for water and then things like the sill drain holes if there are any

How much fuel in the tank? This sloshing sound has been mentioned before on here when the tank is between 3/4 and full.

Thanks for your previous suggestions. I have removed the spare wheel lining tray and the well is perfectly dry. I have noticed the issue from a full tank of diesel to now which presently has about a quarter tank full. Do the cills have drain holes?

Get under the car and you will see several black, rubber bungs running down the car. I would take a few of these off and see if there’s water trapped in there.
 

Had what you’re describing on an older TT… removed a couple bungs and waited for the water to stop, eventually. 

Mr T Man, thanks for the advice. I'll have a lie down underneath the motor and check the bungs.🙂👍

I have had the sounds of water sloshing inside door cavities even when they have not been blocked. Usually after it has rained or washed car and you first set off.

 

There are baffles in the plastic fuel tank I believe but you can occasionally, hear some slosh from that as well at least I have in petrol models. In a quiet environment, when the car shows the trait, try to rock the car back and forth and listen from inside. maybe even back seat, that is closer to the fuel tank, above it...

Check your rear doors their good at filling up with water ,move the seals at the bottom of door to drain them ,mines done it twice .

Sloshing now resolved😁.

A huge round of applause to everyone here at Briskoda who has offered me advice in finding and curing the sloshing noise in my Octavia.

After your many suggestive remedies Mickvrs220 pinpointed the issue to my N/S rear door filling with water.

Opening the door as usual didn't cause the sloshing sound, but moving it more quickly did.

I pulled away the door seal at the bottom and I must have drained away about a pint - if not more.

 

Case closed and many thanks again to you all.👍💯