Fabia vRS Crankshaft Sensor Access / Oil Filter Housing Removal?

Hi folks.

Recently my Fabia stopped starting and it's throwing up the engine speed sensor, along with a flashing glow plug light. Engine speed sensor code shows the crankshaft sensor.
I bought a new sensor and i've had a go of fitting it myself, but i'm having some problems removing the oil filter housing to get access.

This bolt here, seems to be the last one i need to remove, but  can't get a socket or allen keys onto it




I was trying to avoid separating the oil cooler, from the rest of the housing as i heard the seals can be a pain to line up, but it looks like i have no choice?

Any advice / tips appreciated