XJ8 - how much rust is too much?

[oily mist]

Just got a cheap XJ8 as my trusty old XJ6 is nearing retirement. XJ8 is '99 with diligent service history which mechanically seems sound BUT there's outbreaks of tin worm in some of the usual places, e.g. offside inner wing reinforcement, (suspect there might be something on the chassis rail behind the shock too) and down on the nearside floor/cill return and behind the splash guard. These holes appeared 'only' as advisories on the MOT

Questions I have are,
a) is this car a lemon fit only for breaking for parts? Or
b) can patch welding be economically considered?

If b can anyone recommend a welder in the Coventry area? (surely there must be plenty of guys who know what they're doing with a MIG under a Jag.) And I know it's hard without seeing the job but anyone willing to have a guesstimate on potential cost? (Lets say for a repair on inner wing/chassis rail plus 2 decent size floor/cill patches) I'm not after concourse - more like 'sturdy'.

Thanks in anticipation of the usual PH knowledgable help.

[Jaguar steve]

The chassis rail will probrably be the killer. Get firm quotes for that and then decide what to do with the rest

Once fixed saturate everywhere underneath and inside box sections in Waxoil or similar rustproofing.