Where to find replacement Torx screws for the heatsink

I unfortunately messed up my thermal paste reapplication by completely breaking the head off two of the Torx screws clamping the heatsink down to the CPU on reassembly, thinking it had to be tight for good thermal contact.

This means pressure is no longer distributed evenly on the CPU as the remaining screws are both on one side and it will probably fry if I turn it on, which I don’t want to find out…

Unfortunately I have looked everywhere and it seems replacements for these screws are low in demand and not really available apart from shipping them in from the US (I live in the UK) which is a last resort due to the ridiculous price.

I first wanted to know what size these screws are as this is not mentioned in the heat sink removal guide, and if there are any similar screws from different MacBook models or a different part of the laptop.

Is there a unique Apple product code for the screws so I have an easier time looking for them online?

Thank you very much for the help!!