Picked this up today and everything I find points to this being an original mint set issued by the Royal Mint in 1953. Some haze over most of the coins, but in better shape than most of the sets online. According to Numista there are 2 obverses on the 1953 half crown with OBV 1 being issued for the "plastic sets". The half crown in mine matches the PUPs of OBV 1 as well.
Dug this set up again and took new pictures. The luster is there, hardly any marks on the coins; some toning and maybe haze. Overall I would guess MS 64 or better on all the coins. First year of issues for Elizabeth II.
Remarkably tough to photograph through 69 year old plastic, but the luster is visible through the toning on the farthing.
The ship on the reverse of the half penny is stunning, IMO, even with some toning. No PM marks that I can see. Interesting die scratch or crack through ETH on the obverse I just noticed from the pics.
The three pence has the most luster present. More marks on this one but some of those could be rough planchet not struck out. The reverse is pretty awesome.
The blueish tint on portions of the 6 pence is likely from indirect natural light. The cupro-nickel coins in this set have a muted luster, almost matte like and likely from the plastic (and almost 70 years of time).
The one shilling with the Scottish shield on reverse. One hit with a reeded edge above the O in one on the reverse but otherwise really clean in the primary focal points.
One shilling with the English crest on the shield. This has one reed hit on the obverse but otherwise pretty mark free.
The Florin. Overall these dont have great strikes and so a lot of planchet roughness remaining and design elements not all fully struck out such as the top lion on the shilling above.