Congratulations on buying the very best folding bike brand.
Please be aware that simply changing the (standard) "M" type" handlebars to the "S-type" handlebars will not give you a bike with the S-type bar height as the actual handlebar stems are different lengths for the two bike types. You can buy aftermarket handlebars for example from Joseph Kuosac that will drop or raise the height of an M-type or S-type to suit what you want to achieve, without the need to change the stem.
Obviously, you need to consider cable length (and the market as British bikes for the UK market have the right brake lever working the front wheel, whereas in a lot of other countries it's the opposite way around).
I have owned Bromptons since 2009 and they are fantastic. My younger Sister tried mine and fell in love with them. She now owns about 38 Bromptons and is admin of about a dozen FB Brompton groups.... plenty of info out there as well as here.