Cost of replacing immersion heater pulsacoil 2000

Our pulsacoil 2000 stopped giving us hot water and has sprung a leak out of the booster immersion part. We had it rerouted to the bottom heater and were advised we need to replace the top immersion heater and were quoted £540+VAT for parts and labour. Is this quote too high? Looking at some immersion parts online they seem to cost less than £100 inc vat.
They quoted labour time of 90 mins, is this correct?

Where are you located?
It does sound really expensive
Mike

I am located in South East London.

Right.
Look on here home page list of advertisers.
Mario may cover your area.
Or Google up Gledhill repairs for your area.
Or contact Gledhill Response who may cover your area.
They will give you a fixed price repair if they do.
And that will also include 12 months parts and labour too.
With the option of renewing yearly.
Also depending on the unit size and the drain off condition the job could take longer than 90 minutes.
Could take 1 to 2 hours to drain.
Fit the new heater.
And re fill the unit.
Total time can be 2 to 4 hours.
So in retrospect it would seem the estimate may not be correct.
Perhaps lack of experience.
Mike