Acquired my 1st jag an 03 x type diesel only two hopefully minor problems,1 the bonnet catches won't engage and 2 after a jet wash an ice symbol is lit up on my dash any one know why this?

Welcome to the Club, Andrew.

I don't know the x type bonnet catch system, but a squirt of WD 40 might assist,

The Jet wash might have cooled a sensor and the car thinks that the temperature is lower that it is.

I never use a jet wash, but stick wth the bucket of water to get road dirt off, a bucket with shampoo, and then a final bucket to rinse.

Regards,

Peter.