[DJACID]

Looking to buy a RPTV,

been looking at some and notice a Sony which said -
ATSC Integrated High-Definition Tuner

Does that mean its got a HD digital tuner so it can pick up Channel 4 HD,
or is it a conversion thing,
converting signal to digital HD...

[andy1249]

ATSC tuner - Wikipedia, the free encyclopedia

[Alphathon]

Does that mean its got a HD digital tuner

Yes

so it can pick up Channel 4 HD,

No.
ATSC is the American Standard. To get CH4HD you'd need a DVB tuner of some kind, either DVB-S2 for Freesat, DVB-T2 for Freeview HD when it launches or an HD cable box