MoliPlayer has seen an update to version 18.104.22.168 which added a mass of new features.
One of the stand-out improvements is the ability to play video stored on a DLNA server such as PC,NAS or Wireless HD.
The app supports RMVB, AVI, MKV, FLV, FLAC, APE and more and also subtitles.
The video player costs $2.99 with a free trial and can be found in the Windows Phone Store here.
Thanks S.M.A.Sithick for the tip.