The SLX triple is sub-£100, the double more like £120 if that makes a difference.
The new double has shaped tabs that don’t look as though they’re intended to have anything fitted to them on the outside face – bash, outer ring or anything. If you want to fit a 32t chainring, then as pointed out the extended shaped tabs might clash with the chain, or at least prevent you getting a chain guide low enough over the chain.
I struggle to get my chain guide low enough on my XT triple run as a single and that’s with a 34T.
The old style SLX double was the one intended to take a bash ring. The new doubles are more trail/xc set up.
I would think the triple is the one you want and definitely if you want to fit a bash ring.