Quick master cylinder question please

Ordered a new master and slave for my Freelander 98 2l diesel . Anyway it came today and i've only had a quick look in the vehicle . Can see how it goes and have removed the slave ready and disconnected the master from the pedal BUT it looks like the plastic shroud 'thing' is way too big to pull through and also that the new master will be too big to push through from the bulkhead . Like i said i've only had chance to have a brief look .

Am i being stupid here or am i missing something obvious ? Or perhaps they've sent the wrong part , or i've ordered wrong part !

Also , if these units come in one piece , how can the plastic on the inside fit 'round and over' the hole on the inside by the pedal ?

Needs to turned at 45 deg angle.