You'll really struggle to drill thru that bolt......trust me i've been ther!! I tried drilling, heating, impacting etc and it wouldnt budge, so instead i dropped the strut down bent the fork on the strut and squeezed the lower sus arm out, with this out, i put a socket over the outer metal edge of the bushing and used a bearing press to push it out, with that out use the press to put a new bushing in and re-assemble.
This has happened to me 4 times!!
Hope this helps you!