Don't know where to post this, but I need help

I had a service today on my 1.3 golf, and everything seems to be fine aside from needing to change a couple of spark plugs.

I drove my car to work and back, and after about a mile's drive, there was quite a loud sqeaking noise , which sounded like it was coming from the bonnet, I panicked not knowing what it was. Turns out its none of the running gear, As with the bonnet open it's perfectly normal, but as soon as I shut the bonnet with the engine running the squeaking starts, and its making my car sounds like its about to explode. I've looked and I genuinely don't know what it is. Anyone got any ideas? Its only started today.

Cheers.
Josh

Does it squeak on tickover with the bonnet shut or only as revs increase.

sounds like slipping belt.
Could be glazed or wrong size fitted.

It squeaks on tickover as well, yeah. Glazed?

If it was the timing belt, why would it only be squeaking with the bonnet lid shut?

glazing occurs when the belt slips around the pulleys.
the friction rubs the areas smooth and it looks smooth and shiney.
Not sure myself the significance of bonnet open or shut.
I had a similar problem and I had a new belt fitted and it carried on squeeking after a new one was fitted because the wrong size was fitted by the garage.
Another squeek could be the bearings on the alternator going.