Hi frank
You may well be right, the trick is proving it. Finding photographic evidence is tricky, none of the books I have mention the PRV at all, nor that there were variations.
Just figuring out the casting marking differences - ESC(C), KL, FHL - was a case of looking at lots of photos, where the markings are reasonably visible, the PRV by comparison is mostly invisible from the ground, so a bit of a challenge.
Mal
Just going through photos on FB chieftain page, as you stated MK2 were not present, the ones I have found showing that area with Jerry can mounts do not have either present. So looking at base workshop change on new NBC pack fitting and possibly different ones for different manufacturers turret. Just my hunch
Hi Frank
Had a look at some of the walkrounds I’ve copied - Two ESCC turrets with wedge (Rectangular plus) - Saumur Mk10 01E__ (out of shot), & Atilla Mk 11 O5EB71.A Mk 10 in a Dutch museum - KPL1 W EIBRINK - has wedge style, but not sure who cast the turret - clutter (spare periscope heads) on turret roof (if ESCC), where the KL marking should be (LHS turret by MBSGD power lead) is just out of shot, so maybe a FHL (under Commanders stowage box, usually only visible on wrecks).
Or are you thinking of a general midlife upgrade, no matter the manufacturer?
Need to do some modelling, working on the cupola
Mal
From The two production lines I gather the turrets were not interchangeable !!, Will need to look at my books again,
I haven’t gone to the depths, you are going to, by check things with manufacturers markings.
Hi Frank
I didn’t know that about the turrets - the non interchangeability - but did know they had different thickness of armour, but not who produced the thickest.
I wonder if the thinner armoured ones were faster, I recall listening to Lindybeige about the mild steel Cromwell in WWII (training vehicle accidentally issued) being very fast, but not so good when hit.
In one of my Chieftain books it mentions senior officers would try to get the fast ones, which might have implications if things turned to custard?
Mal
Faster is a term that never applied to any Chieftain in any form lol … I was going across Stapel Trg Area near Detmold at full speed taking driver training, when out the corner of my eye, I saw a Leopard 1 coming up, and then over take me in reverse … I jest you not…
On a serious note, and bizarrely, the OC Chieftain dozer tanks always seemed a little bit faster, as they were almost perfectly balanced and got up to speed quicker. But to counter that they were a nightmare trying to stop when at full speed.
Just to clear up the Leo in reverse going faster … We were both going across an undulating Dvr Trg area but my driver was seriously flat out when we were overtaken …very embarrassing …
Hi Johnny
Faster is a relative term here and only applicable to Chieftains - Leo’s & Scorpions need not apply.
Interesting about the Dozer tanks, had only heard they were a nuisance - extra length & weight not being appreciated.
Mal
I wouldn’t say nuisance, more …not really needed to be honest. The dozer was handy for slicing through trees but that was about it. And they were prone to not working to well and pain to set up and get working.
Hi Johnny
Sounds rather like the Aussie experience with Centurion dozers in VN, though don’t recall mention of using them on trees specifically.
Mal
It was never done intentionally Mal, more to do with the driver being a clumsy oaf and not steering left or right in time lol…
I may have mentioned it before but when deployed on a Summer Sales CPX we were transiting around Hohne, admittedly in small packets but driving at a fairly respectable speed, when a Dutch Leopard bridgelayer overtook us. Now, it was minus its bridge, but to have your Land Rover and trailer overtaken by a Leo populated by grinning, long-haired peace-signing Dutch soldiers was a liitle bit disconcerting to say the least!
Cool memories, so, when can we expect the Dio?
Mal
Mal, I don’t know if that was for me but you’re right: a Leo overtaking a Land Rover would look pretty cool. Now, who makes a bridgelayer? PSM? I’ll have a look.
Bridge is NOT included
Curse you Robin, curse you! Now I can’t get the idea out of my head; a bit figure intensive but could be quite charming - well, in a way perhaps. Mind you, arguably a lot of effort for a realtively mundane vignette.
Hmmm.
But it will certainly convey a message from the artist (you) to the viewer 
A tank commander with head and shoulders out of the hatch with a scarf streaming in the wind behind him. Wearing goggles to protect against the wind and both hands holding on to the hatch frame.
Maybe a little flag on an antenna bent backwards from the wind resistance.
As my niece would say - OMG, what have I done/"
Inspiration - Tick
Perspiration…?
Mal