Alcove shelf advice

[PaulC78]

I've got some shelves in an alcove - I say alcove, it's actually one side of a fitted twin wardrobe that has been repurposed - which have been up for the best part of 20 years now. I'm decorating soon and will mostly just be giving this a lick of paint, partly for budget reasons but also because the current arrangement suits me well enough.

Shelves are solid wood (pine I assume, but they're painted), 96 x 49 cm and each supporting a weight of up to 20 kg. One of the side walls seems to be plasterboard, other side and rear wall are both masonry.

Each shelf is held up by plastic rigid joint blocks, two at the back and two each side. I won't know what screws were used until I pop them out.

My question is, am I fine sticking with these plastic blocks to support the shelves (they've been ok for the best part of two decades) or should I be thinking about alternatives, like battens or metal angle brackets?

 

[Cabinetman]

Don’t see much point in changing anything if you’re happy with the setup. They do sound as if they might be a bit ugly, but only you can decide on that though.

 

[PaulC78]

This is how it looks at the moment:



While I'd be reasonably content leaving this as it is, I've been leaning towards battens as I think it would look nicer. I was looking at some 21mm x 36mm pine stripwood for the battens, would that be sufficient? Could I get away with 21mm x 21mm, or would that be too narrow?

On the other hand, the shelves aren't perfectly flat. That's not an issue in terms of usage, but might leave some unsightly gaps when resting on a batten?