Torx first, if that fails just drill the head off. It's amazingly quick and easy once you've done it once.
As drilling out could be tricky, you could epoxy glue a allen key in there, as these are not very tight it might do the job ?
If a torx fails I would use up one of the cheapo allen keys (supplied with furniture) and MIG weld it into the head. the concentrated heat down the shaft often makes it quite easy to remove afterwards
Or get an old torx bit & knock it into the rounded part. Then carefully unwind the sucker free! Here's one I did earlier...now back to the original oil cap type!
Dont buy alu replacements. These shit themselves with ease. I tend to order from dealer any replacements i need. Stick with steel.
Normally a good idea, but in this case, (I don't want to damage the plastic around the bolt) the heat might do damage to the plastic's it is holding in place.
My twopennith. Avoid easiouts like the plague. Unless you are dead centre and very careful the chance of it snapping off is high,. Then you are fooked Get Allen 1/2" sockets like this https://www.amazon.co.uk/drive-Allen-socket-metric-sizes/dp/B00HPY948S
Before I resort to bashing a Torx bit in, I generally search through all my Allen keys - invariably I find an Imperial one will fit better than the metric one.
Try these there more suited for shallow headed things like yours. Damaged Screw Remover and Extractor Set by SKmoon,Easily Remove Stripped or Damaged Screws. Made from H.S.S. 4341#, The Hardness is 62-63hrc,Set of 4 Stripped Screw Removers https://www.amazon.co.uk/dp/B078BFD8J2/ref=cm_sw_r_cp_apa_i_aIYXCbRP93Z8R
also copper slip all replacement bolts if you check eBay there are various sites selling stainless fasteners of all descriptions, just sit them in a bit if cardboard and spray them any colour you want.
I have used these with success a few times,as you drill in it should take the head off the bolt, then remove part and remove the remainder on the bench.
