hmm i'd take it back to the garage that last fixed it and tell them the bonnet wont open after they last fixed it and would they mind opening it up (pretty please
it shouldnt take them more than 10 minutes to pop it open, then you can see what other fun is lurking under there waiting to pounce on your wallet.
the scuttle panel end rubber flaps (over the tops of the rear of the arches just in front of the door pillars) will have slimed up, which is why you have a boating lake just under the edge of the windscreen sloshing about.
you could try chucking some clothes washing up liquid in the edges of the windscreen to see if it helps unstick the flaps, along with some hot water (as long as its not freezing/frozen cold, the glass that is) a bit of net curtain wire or wire coat hanger might help to ope the flap up.
you'll know when it works, as you'll have soaking wet feet
you are going to need a new cabin air filter now as well, as yours is all muked up with water and whatever gunk was sloshing about on the scuttle panel.
one of my previous posts has the long term fix for the scuttle panels low vent lip problem.