In the UK? I know Expert Stylus and Cartridge Company. They have done several jobs for me, consistng of retipping, and cantilever replacement with excellent results and prices.
They have no website, but will answer your e-mail inquiries at: email@example.com
Your particular Denon might be better replaced with an original.
But if you want a repair which includes some sort of upgrade (a sapphire cantilever and Paratrace Diamond?) you might request information from them. Highly recommended!