Bonnet Stuck

[McP]

Hi folks

I am currently unable to open the bonnet on my 2000 Alfa 156. I release the bonnet catch under the dash (stage 1) and all seems OK. I then lift the under-bonnet catch (red plastic lever - stage 2) and attempt to lift the bonnet but it will not lift. It feels like the second stage is not unlocking. Has anyone else had this and know what to do. It's going into the dealer tomorrow but I'd like to fix it myself if possible

Thanks
McP