Hot water pipes ie to taps

Flexible tap connectors shouldn't just burst as manufacturers test them with higher pressures than would be normally expected in homes. Inspect the hoses, I guarantee you they were both kinked hence creating a weak point for the rubber to split. It's fine to replace like for like. Though any plumber will tell you copper is superior.

i would use copper, but flexi hoses are ok. my guess is that they were old and if you had a new combi installed was it converted from a gravity system, as the pressure would have increased with the combi,