STOP!!!!!! Do not heat up the crankshaft bolt!!
Get the engine upside down on a stand, some failures of the big end bearing have been documented but nowhere as bad as the 12 valves. Remove the sump and wedge wood between a crank throw and block.
Now get a 'proper' hardened six sided socket and then tear up pieces of your best porn mag, lay a piece over the crank bolt and push the socket over it, keep laying on the paper until you have to tap the socket on with a mallet, only now use your rattle gun, or very long bar and of course hurl foul language at it, then it will undo but, if you use heat it tends to anneal the metal in the bolt head and it softens and rounds or snaps off...not advisable right? When all tightened up now replace the big end bearings, they are so cheap it would be IMO foolish not to do it right now.
Next, the UK version got a serious clutch and as per my PM the 24 valve got a larger version than the 12 valve, the pressure plate takes some serious effort to release, UK versions had a servo on the clutch pedal, a smaller version of the brake servo, with the engine off it will be quite an effort to operate the clutch comfortably, with the servo and the engine running it is as easy a typical saloon car.
regards
Dave