I don't understand, the Whale Elite is a single lever mixer or at least the one in my Pageant is.
I'd guess it's split due to frost - it's important to leave mixer taps open in a central (hot + cold) position as well as draining down the system and leaving other taps open.
Fitting a replacement Elite is basically straightforward BUT access may be difficult. It's often easier to take the sink / drainer out to do the job.
Current production Elites are claimed to be improved, frost-proof by Whale but they still need treating properly over winter.