Recommendations for a £2k / $2.5k digital only system please

A friend has asked me suggest a digital only (Spotify connect) hifi system for him with a budget of about £2,000

His room is 5m x 5m and music tastes lean towards experimental electronica e.g. jon hopkins so a solid bass performance is essential. no neighbours to worry about.

From a value perspective i am expecting to look at pre-owned kit but new is also fine.

My first thought was a pair of KEF LS50 Wireless (about £1400 s/h) plus one, or a pair, of small REL or SVS subs at about £300-400 each. 

He has young children so i was thinking the KEF’s could be positioned high on a shelf and probably go for a downward firing sub.

Any thoughts on this combo or other suggestions?

thanks v much.