Rather than a patchwork shielding of the destination, why not cut off the source?
The resolution is simple: complain to Sky Broadband UK that one of their customers is using their services to generate unsolicited spam, backed up with IP records as evidence. Even where proxies have been used, they should be able to tie that in with Franko's IP accessing the proxy at the relevant times.
Internet service removal, Goodbye Franko, headache gone, internet happier.
He's given all the ammunition required, it's just whether John has the time/will to do anything about it. Alternatively, he could ask a UK representative to manage the complaint on behalf of the site (no work/effort for John) to accomplish the same.
I stick by my initial feeling on this: it's like watching a blog of someone going through a nervous breakdown.
