Work kit bag with a Brompton - what will work?

[TPMB12]

I now have to carry my things everywhere with me to site and around site.  No permanent desk or office or locker. Mostly WFH anyway so it's only the odd day I commute by train and Brompton. Kit includes safety boots,  overalls, laptop, headset,  filofax,  notebook and paramo jacket if not worn. Plus insulated mug.

The Brompton bags look like messenger bags but the rucksack options are 17 or 20 litres. My work supplied laptop bag is supposed to be 16 litres and is too small. I can't get anything else in it so certainly not boots and overalls. Is the 23l large metro messenger bag or the 28l Borough big enough do you reckon? I'm not sure the boots would fit a messenger bag.

[drossall]

The larger Brompton bags are quite capacious. They might fit everything except the boots. My insulated mug goes in one of the rear pockets on my older C bag.

I'd combine the largest front bag I could find with a Uniklip bag (not a pannier) on the rear. The Uniklip fitting works well on a traditional Brompton rack. You can either buy one of the various brands that make bags with Uniklip fittings or, as I did, buy the fitting and attach it to your own bag (which I bought second-hand for the purpose).

I've carried my hiking boots to Scout meetings in mine, so it should work for you. A roll-top bag is good for this.

[hbunnet]

Consider safety shoes instead of boots. They'll fit in a bag easier, or wear them on the train.
No good if you are working in a dirty or muddy place though.

[D.A.L.E.]

I have a Borough and I really rate it. I think it would fit? I can get a fair bit in mine, similar stuff, I don't think I've even come close to maxing it out.