Which Zone Control Valve?

[RonMig]

Which brand of zone control valve would you recommend? (22mm, 2-port)
Choices from Screwfix and Toolstation are Honeywell , Drayton, Danfoss, FloMasta, Corgi, Sunvic, Salus
- other makes and suppliers are presumably available; these are local so, quick and easy to get - but I'm open to other options.

a bit of history -
Our original system was installed by British Gas in 1993, used Landis & Gyr 2 port zone control valves, model za-v222.
One for hot water and one for central heating, fed by Baxi Solo boiler & going to 11 rads and a giant h/w tank for power shower
The original ZCVs lasted until around 2007, although I did replace both the syncron motors at some point before that as well.
I replaced both the c/h and h/w complete ZCVs with L&G lookalikes, Tower brand, model VAL222mv.
I also subsequently replaced the syncron motor in one of them (hot water, I think) in 2017, which is also when I put in a new Grundfoss pump.
So now, the central heating ZCV is stuck open, with boiler running even with control panel set to "off". Not the worst scenario, I know, at least the house is warm.
Given it's age I reckon the valve pivot is stuck open, pressing on the switch, so calling for heat and activating the pump.

I'm going to replace both valves so I can hopefully forget about them for another 10 years (!)
I've noticed some ZCV types are modular, so can replace the powerhead (£50?) and leave the valve in place - is it worth going for this type rather than just switch the £20 syncron motor?
Also noticed some ZCVs have plastic powerheads rather than all-metal - doesn't the plastic degrade & go brittle with the heat?
I know the ZCV prices range from £25 to £85 each, I want longevity & reliability, not just cheap.

When these ones need replacing I'll be too old to want to do it myself...

Thanks

ps, I know you like pictures... so here you go -

and yes, it's a bit tight in there... access is not brilliant

 

[MoreWellie]

That looks potentially worse than mine as the third pipe at the back doesn't look to have a joint on it. I have absolutley no idea why they didn't design the valves with a flat flange face like the pump

my experience is sunvic and honeywell and Honeywell definitely last longer in our installation

I could be tempted to try the Drayton valves next as the heads simply unclip and are available separately. Saw them fitted by BG on my parents heating. They still fail though as that was why I was looking at it

 

[brightspark]

just get the tin honewell; ones .mines lasted donkeys years. 2nd one in 40 years/ go on ebay you can normaly pick one up cheaper than screwfix or the plumbers merchants

 

[waddycall]

I’d go with Honeywell. You can change the motor or head if you need to. The plastic ones do go brittle.

 

[RonMig]

the third pipe at the back doesn't look to have a joint on it.

that one has got a gate valve on it, hidden behind the c/h valve - I believe it's the safety bypass.

 

[Kayos]

Honeywell unless you like changing them on a regular basis

 

[hunter27]

Honeywell, unless you need them in an emergency they are usually much cheaper on Ebay than my local suppliers.