I use the AOHI charger (40W PD) to great results. I use it with my 14" MacBook Pro, and it does work best to charge it overnight, etc. when I'm not using it, but it does work when using the laptop. It's probably the lowest I would go.

When charging two PD devices, (i.e. an iPad Pro AND a MacBook Pro) it does split the charge, and it will run the MacBook without charging it, but don't expect it to charge both quickly at the same time.

Personally for the size/weight tradeoff, I'm ok with the limitations, and haven't run into any issues where it prevented me from working. That being said, 40W is probably the lowest I would go.

Alternatively, I would go with anything from Anker that has the output you need. Never had an issue with any of their stuff.

Edit: Just saw another comment that OP is UK-based. In that case, this is what I would get since it allows you to swap out the outlet par of the adapter: https://www.amazon.com/Charger-Anker-Intelligent-Allocation-PowerPort/dp/B083Z5JBH4/