The Brompton is worth every penny – well mine is – I have a 2016 S6L – compared to a road bike it accelerates like a rocket, and dont forget the rear suspension, also it is very stable and you can forget your riding a folder with 16″ wheels.
I got mine from the bike shop in Malmesbury- they are official dealers.
Mine was thier Demo bike so I got a £1050 bike for £750
I tried the “m” bars but found them too flexy – the Straight bar has a slightly taller stem and is rock solid.
My only warning is that when you hear something rattling on the back- dont ignore it – its the derailiuer bolt which goes in from underneath. I was lucky though otherwise it could wreack your back wheel –
Also on the New Intercity Express trains mine doesnt fit (all the way) under the luggage rack as I have the extra long seat post!!!
I used mine from Swindon to NEC (12 miles a day) for a year and its still rides like new. it paid for itself in 3 weeks!
I love mine and even though I dont commute on it now I am keeping it.