There are limited options for UK specific Website buyers in terms of a platform, different places look for different factors to what they consider to be valuable.
For example id imagine most here would look at the domain value more than than a general buyer would, sites such as flippa (There are UK buyers there too) people tend to look at multiples of revenue and have very little focus for anything else.
Some higher value buyers which you only find through closed groups of people often value a more rounded outlook such as domain value/authority, Under used Mailing lists , social aspects, traffic and over all potential, they often keep a 3rd eye on Facebook domain and Site sales pages too but only pipe up if there is something of interest, as with any page open to the masses you will always attract the idiots who derail everything and anything.
On the other side of things if the site is profitable you maybe able to sell it as a business rather than website.
Off the top of my head i cant think of anywhere other than flippa, Sedo, businessesforsale.com and various forums ( like mentioned above ) that are available publicly.
Never thought of domainlore , is that ok to use non-uk TLD's ? although still targeting the UK audience ?