if this is whats being referred to... this would only apply to ar-pistols (or other braced pistols) with a vertical foregrip AND a brace on a folding adapter that is under 26" without the brace used for the measurement.
so all you need to do is remove the VFG and you're back in good territory - at least as far as the required stamp for an AOW is concerned.
the BATFE has always taken that a pistol cannot have a VFG, and this ruling appears to clarify that a brace is just an accessory (which keeps it from being classified as a stock, which is a necessary part of a rifle or shotgun) and therefore not relevant to the lentgh measurement of your braced pistol.
i dont see anything regarding angled foregrips (which have been ok for a long time now) so just drop the VFG off and get an AFG and you should be in ok shape.
now - i am not a lawyer, but i did stay at a holiday in express a few months ago.. so... take it for what its worth.