Its difficult to know whether it would be cost effective to fix.
A ticking noise can sometimes be a failed / sticking injector but if it is coming from behind the timing cover, it would suggest timing chain/ tensioner / guide / pulley issues ?
If it is 'just' timing chain related, replacement with the upgraded items is likely to be between £2k-£3k at a specialist.
If any internal engine damage is the cause of the noise, it seems that parts are tricky to source, most people then try to source a second hand engine.
Prices seem to vary between £5k-£7k, but then there is the fitting cost on top.
Fixed, the car is probably worth £9k-£11k, based on asking prices on Autotrader.
Might be worth speaking to other Jaguar specialists to see if anyone else has come across the problem, taking a video on your phone might give them a starting point.
Breaking it yourself is a hassle, some bits sell quickly, others don't, you then have to find a way to dispose of whats left.
No idea what a specialist breaker would offer you as a complete car.
Probably worth putting up some more details of interior / exterior colour combination and see whether there is someone on here that fancies a project ?