No question: Brompton. Quality machine, good to ride, robust and comfortable. One fits behind the seat in a Pup, or did until it was crashed - the Pup not the Brompton unfortunately. Get the kevlar tyres to remove the risk of punctures and they last for ever. I was so impressed after miles & miles of commuting and carrying it on the train, that I bought a second for my wife and the two Bromptons fit in the storage locker of the camper.
They are pricey but quality costs, and if you decide to sell later it will have retained it's value.
Exactly what you need for independant transport when on detachment with the 146! I took mine on the Herc (aahh! Snoopy) to Ascension and it was great fun.
Jim