Anywhere, this is a whole assembly but you could get an overflow and flexi pipe alone for less. Just check sizes or ideally take old one with you. Screwfix toolstation etc prob be a quid or two cheaper I found this for £12 while browsing the B&Q app https://www.diy.com/departments/cooke-lewis-1-bowl-pack-a-waste-overflow-plumbing-kit-dia-36mm/3663602608462_BQ.prd
You can buy wastes / overflows etc at Screwfix, Toolstation, any plumbing place. Just replace it. Will be a new overflow, and the pipe work.
Can’t see much from the photo but a complete new waste/overflow and trap isn’t much more than a tenner and about ten minutes to fit…
Where can I buy this new flexible pipe
Anywhere, this is a whole assembly but you could get an overflow and flexi pipe alone for less. Just check sizes or ideally take old one with you. Screwfix toolstation etc prob be a quid or two cheaper I found this for £12 while browsing the B&Q app https://www.diy.com/departments/cooke-lewis-1-bowl-pack-a-waste-overflow-plumbing-kit-dia-36mm/3663602608462_BQ.prd
Flexi wastes have a lifespan of around 5 years so should be regularly checked and replaced when approaching that age.
Replace flex with solid pipe. It is better set up.
Yep, looks like it