hi welcome to the forums.
there are x2 bonnet locks on the lag1 just behind the headlamps and a sprung safety catch in the middle, up under the badge.
bonnet release is via handle just forward of your left knee on the bottom of the dashboard.
if you are having problems getting it to release from only the handle, get a mate to press down (prefferably without metalwork on hands) to release pressure on the bonnet catches, you then pull, and hopefully the catches will release.
its very common for them to gunk up and seize, also for the 2 cables (one with handle on end passes through the bulkhead and across to NSF catch, with second shorter cable connecting onto 1st catch and running across and just behind the radiator to the OSF catch) to stretch or have thier cable end clips to break off, if repeatedly pulled to hard.
if you still get no joy, then it might be worth asking a local garage if they can get the car up on a ramp to enable them to reach up into the engine bay to release the catches from underneath.
replacement dealership prices are: new catches are about £35 each, main bonnet release cable with handle is £22 and short cable is £10
catches should be clean of grease and
, as any on there will promote buildup of road gunk and cause failure.