I've had a call with the Sage ISV Network, and I will review the new process for marketing one of our Sage 200 add-on's via the UK Marketplace. I've taken a look a the process for a Sage 200 end user to set-up a Market place account (not too time consuming, but not quick). I'll also await to hear back if the 'lead' from a Sage 200 UK marketplace ISV application (app) enquiry is passed to the Sage 200 BP of that user (in addition to the ISV).
The Sage UK additions site has many Sage 200 'additions' from the various Silver, Gold and Platinum developers (and developers with a certified product). This site has limited search features (just filtering by a couple of filters). The UK Marketplace search and info is a massive improvement. We provide several sage 200 add-ons (not just one product) so additions has never been an option for Marketing our Sage 200 solutions (as we would have to certify each add-on).
Hopefully as the UK Marketplace evolves, this will be of benefit to more Sage 200 developers and ISV's.