PPE, or indeed uniform, doesn't need to be company-branded. Else every pair of gloves, wellies, steel toe-capped boots, trousers, skirts, hi-viz, etc would have to bear company branding. If Grand Central decided tomorrow that their uniform was going to be logo-less plain colour navy and orange shirts and trousers/skirts/shorts, they could legitimately provide that as uniform. When my employer gave me gloves, hard hat, boots, and hi-viz, they were considered PPE despite not having the company logo on.
If a company had staff working outside in the sun all day, I'm pretty sure they could give staff suncream as PPE and not be liable for tax. The HMRC tax manual isn't that prescriptive to list suncream specifically, but I can't see how it could be argued against (and I don't think even HMRC would want the bad PR of appearing to 'ban suncream' for staff working outside 8 hours a day). I would add though that to avoid personal use coming into play, an employer would be best off keeping the suncream on-site. We wouldn't consider hand sanitising gel a benefit-in-kind for tax purposes, so I'm not sure we should could suncream any differently.