i have just got a couple of
570056 - "Actuator for 570055&617499&750404" (An extra actuator)

when trying to fit to my TRV the thread on fht is a couple of mm to big to fit.

I notice the adaptors are all for TRV's with no thread,

Are my TRV's just a bit smaller than standard valves, or is trhere an adaptop to make these fit.

has anyone else had any issue fitting them, if it is my TRV's that are not standard i think i may have to replace them

If i do replace them, is there a standard size i should ask for or should they all be the same.