Just an update which might help people in this quagmire of a niche.
I discounted DatingFactory per advice of BG and other posters in the thread - thanks again.
I contacted HubStars (part of HubPeople) and received a frank and honest response, given that they could have easily grabbed what they could. Their reply as follows with my domains redacted:
Hi Dale,
I'm Jaclyn the new account manager here at HubStars so i'll be helping you with how best to optimise your sites moving forward and to start making profits with HubStars!
Thanks for sending over these domains, ****** looks like it is based on a mainstream website which if i'm honest isn't our strongest niche as we predominantly focus on casual/adult dating. In particular we specialise in BDSM, couples/swinging, transexuals and bisexual/gay which is where we're seeing extremely fast growth lately.
We do have a mainstream database however the traffic to it is low and so if you intend on spending on marketing this site, the performance metrics may not be strong enough for you to see a return.
With ***** -  again, seemingly a mainstream site and the traffic in this region is very low, so you can certainly give this a try, however the ROI may not be great on this.
If you have any domains within the casual/adult niches, then we can discuss the opportunity in more detail as there is certainly some great money to be made here.  We are growing at an astounding rate right now and so now would be a great time to take advantage of these niches and start driving traffic to HubStars.
Best Wishes