Need help changing a toilet flush mechanism in my bathroom

I’m looking for a qualified handyman to replace the toilet flush mechanism in my bathroom. The current unit seems worn out and leaks occasionally, and I’d like a reliable, water-efficient model installed. Ideally, you have experience with standard dual-flush systems and can handle basic plumbing tasks without causing further issues. I can provide the new flush kit, or you can recommend a compatible unit. Please confirm you can turn off the water supply safely, test for leaks after installation, and leave everything clean and functional. Local work in Ireland is preferred, and accessibility to the bathroom should be straightforward.