I had a 88 XJS before I purchased my 02 XK8 and really NEVER had a major issue with it, even with the V12!! Just wasn't a convertible.
Since I bought my XK8, it's been in the shop or I've been under the bonnet more than I've driven it!! Here's a list of what I've had to do since buying.
Complete service
Rear shocks
Hydraulic top hoses
New brakes and rotors
New spark plugs
Most of coolant system replaced
AC work done
Several cracked plastic couplings and parts replaced
New window switches
New sport switch
In the process of new tires. Had to order.

All of these things worked or seemed fine when purchased but reared their ugly heads within three months. (Except tires)

Had the engine build number checked and dealer says mine has last tensioner type and should not need replaced. My mechanic also says they look good as well.
At idea of what I am looking at next?!?!
My mileage is 90154. Ay modules or relays I can look forward to replacing soon???

 

Your battery will fail within the next two months and you are bound to have several annoying electrical faults which will trigger Restricted Performance. Well that's what's happened to me so far anyway. Could be worse though you could have bought a Lamborghini!

Whatever happens just keep smiling it works for me.

Here's wishing you happy fault free motoring from the sunny UK.

 

Oxygen sensors, ABS module circuit board cracking and, for an encore, fuel pump failure.
If it was the S/C version I'd throw in knock sensor failure but that's too easy for an XK8.

 

Don't forget perhaps a coil or two, a fuel vapor leak and the power seat module circuit board trace cracks.

Once it is all sorted though, it should be quite trouble free (seriously!)

 

Brake pedal switch, plastic accordion-style air intake duct, and plastic coolant expansion tank hose nozzles....

 

I do have a new battery, dealer installed, expansion tank parts were part of coolant work, power seat working now an I'm only driver so as long as it doesn't reset if problem, I'll live with it. Accordion air intake looks new, very pliable.

Other things, I'll, what was the advice?????, SMILE (to hide the tears, as Sting said!!)

Seriously, I simply love the car and will do my best to keep up with it.
I didn't include the several thousands for the arden kit waiting to install, new badges, wheel centers, new audio, led headlight rings...............

My very first car was a Triumph tr6 second was a 68 xke. You'd think I'd be used to it. Many many others since then.

 

Hopefully you don't have to rebuild the engine like mine..

And then...
Self dimming rear view mirror
Headliner
Sun visor repair...

 

Headliner needs replaced but I'll clean first! Then before I have to replace, I'll try the black fabric paint!!
As far as engine re...... I won't even tempt the Gods.

 

No one has mentioned the transmission A drum failure. That's a surprise. And just because you had the hydraulic hoses replaced doesn't mean the latch or cylinders won't start leaking. And the mirror?

 

Then there's the SRS system, it contains the spirit of Lucas, Prince of Darkness.
Of course over 100K and the troubles really start.

 

And remember, Murphy was an optimist! (third law of Sodd)