Selling my son's Drumit 5 kit. Need advice, please

[Spinball]

Hey folks,
I bought the Drumit 5 kit for my son in 2011 or 2012 when he started playing drums seriously. 
I got an extra cymbal as I felt 2 (1 crash and 1 ride) was too few.  Got to have the 2 crashes for the two hands!  (I'm a drummer myself starting with a very early kit that I can't even remember the name of, then a Simmons SDS9 kit and then replacing the brain with an Alesis D4 for gigs in the 90s).

When he was 13, my son posted a review of his Drumit 5 on AVForums: https://www.avforums.com/threads/2box-drumit-five-electronic-drum-kit-review.1943079/
He progressed to grade 5 and then lost interest in drumming. 

Now, he's heading off to university and as we're downsizing, I'm selling his kit for him.  The kit has been in storage for maybe 4 years and we set it up yesterday in the garage and it is in good cosmetic condition and still works fine with all the bits 'n' pieces present. 
The only issue is that the rubber back and underside of the brain are sticky as has been reported by other owners.

We still have all the boxes (except for the extra cymbal) and the kit is now packed up and ready to go.

I would attach photos, but I suspect that as a brand new user, I don't have the privileges, yet.

So my question for you fine folks is what should I ask for this kit and where is the best place to sell it in the UK?
Many thanks in advance for your help.

[Slamstick]

This is a great place to sell it . As we are the most familiar with 2 Box. Ebay also.As far as pricing , maybe see what is or was  similar selling on ebay. Good luck!   

[Spinball]

Thanks for the advice. 

[Slamstick]

Your welcome , and good luck with your sale