UK Pilot Jet no.15 Long or short

[DeadEyeDoc]

So I've recently been having problems with my old XJ and have been going through the usual bugbears such as dirty carbs, vacuum leaks, fuel pumps etc. However, while I was cleaning out my carbs I removed the Pilot Jet (UK no.15) and one of them was damaged, as though a chip was broken off the slotted head. So anyway, I'm ordering new Pilot Jets and noticed there are long and short ones. Now my carbs have the short types (BDST28 carbs), but I'm now wondering if the long types are acceptable to use.

Also, does anyone know the part number for UK 1995 pilot jets (plastic floats)?

Annnd why is my bike struggling to accelerate in higher gears... (I'll come back to this)