Just FWIW, I would ask this over in r/justrolledintotheshop and see what you get. My instinct would be, no, they're not going to say yes. Way too much liability, and they're not going to risk losing a $175 ratchet to someone who just walked in off the street. But this may be a cultural thing, in the US, a mechanic's tools (outside of dealer-specific or diagnostic stuff like scan tools) are not the property of the shop, but are their own personal ones. The idea being, if they get another job, they simply roll their toolbox out and bring everything to the next job.

Mechanics are infamous for not letting co-workers borrow tools, you think some rando asking to do a serpentine belt change in the parking lot is going to be any better?

The better option is parts stores - at least in the US, most auto parts places have loaner tool programs, where you pay a deposit to get the tool for 30 days or so. And most parts places, unlike auto shops, don't mind as much if you have to replace an alternator in the parking lot. This is also great as a DIYer who doesn't need certain tools (like O2 sensor sockets) all of the time, but maybe once every few years.