Yes, they were a troublesome model the EA, but to answer ur question, no they are not hard to replace and can be bought from wreckers for around $50-$100 depending on condition.
Before replacing, check plugs for bad connection on back of cluster, XF was famous for this fault, and is easily fixed. Use contact cleaner(CRC or equivelent) on pins and socket, blow dry with compressed air.
If that didn't fix it then the cluster itself is probably cactus, and requires replacement.
Remove screws holding cluster in dash, remove cluster assembly(drop steering column down to allow removal of cluster), unplug harnesses from cluster and remove from vehicle.
Before fitting replacement, check all light bulbs on back of cluster, if blackened or mirrored, replace now, you will curse yourself once you put it in and they dont all work, lol.
Fitment is reverse of above.
Invest in a gregorys or haynes manual.