If head is off, then no reason you can’t remove axle.
Gives you two options, I can think of
1. Place in vice, with two blocks of wood with “V” notch cut in each side. To protect and hold securely. Drill pilot hole in bolt and use stud extractor, from Halfords/B&Q etc.
2. Take to local engineering firm and get it done by them.
Edit bolt is hollow so option one no pilot hole needed