Xantia Tailgate Gas Struts

[Saraphee]

I've just changed these as Mrs B says the tailgate, complete with the go faster spoiler, is too heavy for her to lift for the golf clubs to go in.
The result is not much different. Stays up more readily but still difficult to lift up. I'm told that there is not a 'heavy duty' version available.

Would anyone know if there is such a compatible strut, say from am SUV or 4X4? My mechanic is looking but does not seem to know where to start.
Thanks.