Any specialists near Wolverhampton to fix this problem?

Hi Trevor, your post indicates you are in / around Wolverhampton, practically the heartland of Jaguar and I would have thought that every second garage would be knowledgeable about Jaguars.

However, your post is quite light on details. Has the rear subframe got surface rust that could be treated by Lanoguard / Dinitrol application, which most small independent garages can tackle. Or, is the subframe rusted to the point of needing replacement, i.e. large portions flaking off and holes appearing? Which would require a major bodyshop to tackle. I have heard of someone replacing the rear subframe on a 2010 XKR and that work was undertaken by a company called XL Motors of Coventry - a recommendation from the local Jaguar Dealership.

Unfortunately, this is a common misconception about the X-150 Modern XK. A lot of people think the aluminium body means no chance of corrosion, but as you are learning, the car has steel underpinnings and, especially, where the aluminium and steel meet, there is indeed a very high chance of corrosion happening. Especially so if the car is used all year round and experiences salted roads, or if the car has spent a proportion of its life living near the sea.

And, of course, the aluminium body can experience oxide corrosion due to untreated paint chips and the application of a corrosive salt, resulting in areas of white powder appearing.

N6 JMX