When I read "I haven't had an Huanyang VFD go faulty now for at least 4yrs and I've fit over 40 sets just in the last 12 months and probably 200+ in the last 5yrs, so I'd say they are fairly reliable now", that sounds like a "recommendation" to me but perhaps I misread that.

It doesn't bother me either way but based on your experience, I'd replace the old HY with a modern one. No offence meant!