harrydavidson701l3 - Are you sure that the parts he replaced were good ones?

adamhill - You can try bying another one. Maybe the problem is the toilet. Just call a specialist.

alisonin - This seems to be the problem I had some time ago. Never think that something would fix itself out of nowhere. This is a widespread problem among old toilet bowls. I had the same one and had to contact the company www.wilcoplumbing.com.au which quickly helped me solve this problem. In fact, it is pointless to fix old toilets. When I set my bathroom a year later, it cracked, and I still had to buy a new one. I also advise you to buy a new toilet and no longer think that something would happen. Old equipment often breaks down, and you will spend more money on fixing it than if you buy a new one. Maybe my advice will help some of you in the future!

jakej - Yeah, I agree with alisonin's opinion, it will be the best option for you there. Anyway I also suggest you to check some special design services, for example you may have a look at https://matterdesigns.co.uk/bathrooms/ Bathrooms essex or some other companies, there are a lot of them, just don't forget to check all the reviews beforehand.