if you have oil in the dissy than this is why it wont start.
the immobiliser is normaly connected to the fuel pump
and starter or the fuel pump and cars live feed from ignition so that no electrics will work........
with most non spark related problems for you do anything else check the engine earth straps / wire....
99% of the time its theses which cause problems in winter because of all the wet weather they corrode..
if your earths are ok then check the coils you can do it either with a multimeter see haynes book or pull off the coil to dissy cap lead..... leave it on the coil , just pull it off the dissy cap and get someone to hold it near the cylider head like you would with the leads and then crank the engine if you get a spark its not the coil... if you dont get a spark check the low tention wires on the coil ....and try again if no spark coil is faulty....... when holding the lead be careful not to get a shock......