Choosing replacement ballast

[Volt66]

Hi all. I have two bathroom cabinets which each use two T2 15W fluorescent tubes. Each tube has its own ballast which are pretty expensive to replace and go about every 12 months.

Just wondering what ballast would be able to replace both of these, or if anyone can give me some ballast calcs to work from. I used to be a sparky but never came across this.

I'd make the switch to LED but haven't found a strip that gives out anywhere near as much light as these do, but I'm open to suggestions.

Thanks in advance!