Split liner / head gasket symptoms

[craigoodwood]

Long time no post eh....
I'm fast approaching 7 years of ownership with this 850, it passed it's mot again in August needing two wishbones and no advisories and I'm still very much in love yesterday however it decided to test my loyalty and I canny just figure what is wrong with it or what direction to take it...
Travelling home from work as normal, happened upon a tractor and got past as normal 3rd gear 6k while the opportunity was there no problem, few miles down the road traffic had stopped as did I and the car was vibrating and when I could move in wot in 1st and it was misfiring terrible so nursed it home with the misfire and vibration still evident, left it running when I pulled up checked exhaust sounded and smelt normal..... popped the bonnet all looked normal reved lightly seemed fine rev hard it misfires, water water a little low but not below min and oil level fine with normal moisture on dips tickets but pcs was due to be changed in the coming weeks so I left it....
Checked water before I left for work it hadn't moved started it up normal sounding no misfire, tootled down the road and had slight misfire which got noticeably worse once warm, got to work and pulled each plug lead, each injector lead and maf plug off and none made a difference and the top radiator hose was pressurised..... I did get the cap off and it gave a big gurgle but no oil evident in there and no obvious water on dipstick.... drive home similar misfire, vibration but full boost and no signs of smoke.

So if you've managed to read through all that, Google has came up with no exact match so my train of thought is...
Split liner
Head gasket
Bent rod
Snapped cam

but I'm stumped and I don't just know which direction to go now so any input at this point is helpful, by the way it's still the same 95 t5 manual no engine mods bar a 16t cheers craig