Is £380 door to door?
Van to Depot -> Load into container -> Lorry to Container Terminal -> Load Vessel -> Getting to OZ it'll probably be 'transhipped' (unloaded and loaded onto a different ship) a few times so more handling costs there ->
Unload in Oz -> Lorry to Customs shed -> Unpack sort -> Van to your door
+ all of the paperwork customs clearances and fees shipping agent(s) and shiping line(s)
Sea freight isn't as easy at it may all appear, it's just not set up for stuff like that really. If you want a whole container with 1 groupage (1 type of things, 1 customs declaration as opposed to 50+ the way your carpet may end going) from a factory in china to a distrabution centre in Europe then easy and much cheaper.
World wide most shipping lines and terminals have made a major losses this last year
there's a good chance if you sent it sea freight it'd end up going via China as thats where most of the UK traffic is bound and the same for Oz too.
Courier/air freight TNT, Fedex and the likes are a little more joined up door to door put you pay for it!