Brommie - P type has standard butterfly handlebars
NB, rather different.. P bar is an up/down double height vertical bend,
whereas Trekking/Butterfly bars are a near/far horizontal hand position alternativewith a bar end like side position..M bar on brompton takes Ergon grip-shift length GR3s, with integrated bar ends, to create part of an alternative to straight bars.. still folds down..
GR5 will need bar-end/grip clamp bolt loosening, rotating a bit for the fold.. of course the same grip can be fitted on either 7/8" bars.. of course for Canadians have to import both,
GBP is more than the CDN$ 'loonie'[or the yankee dollar] so the international monetary exchange difference also raises the British, and Euro, CHF, imports..CDN$, and U$D seem on par these days..