My guess is the cable between the two latches is still intact... However, on a RHD drive car (OP is in UK) the hood lever is near the right front door ...In the US (LHD) it is near the left door

In any case, you need to manually move the the single latch that will open both front latches thru the grill. See Nathan's DIY explanation below.

https://youtu.be/V0M3m3_CXsY?si=yGsuWjzBk4A-SKW_

Instead of a screwdriver, I use an L-shaped Allen wrench with the long end inserted into a small socket mounted on a socket driver. This gives me a powerful right angle pushing tool.