It was a bit ironic today. It rained for the first morning for a while as I went into Boots to look at sunscreens. I saw the sachet ones that I highlighted before, but there were even smaller alternatives:
Soltan tender places sunscreen SPF 50 15ml (20g), ideal for weekend trips I would have thought.

Soltan Extreme Combi Face & Lip Protection SPF 25 30ml (40g), good for longer trips and has an integrated lip salve. 
As Boots had a 2 for 1 offer and both suncreens have a shelf life of 18 months, I bought them both. All sorted for the sun. I’m hoping I’ll manage a couple of days walking in August. It will probably rain!