Ruined caliper advice needed

[SeriesLandy]

Whilst building up my brake system today I got to the front calipers.
The first was fine, on the second I managed to shear the bleed nipple off.
I tried welding and then drilling and still couldn't get it out. So I've ruined the thread for the nipple.

Can I tap it again and use a larger nipple (what size?) or do I need to get a new caliper?
If so where can I get a new (to me) caliper (its the teves one).

Really annoyed as I was hoping to have a braked car by this evening.