Pulsacoil A Class Eco APA6180 and the red light is flashing

Hi we have a Pulsacoil A Class Eco APA6180 and the red light is flashing.
The boiler is working however we are about to sell our flat and I don't want any problems for the new buyer and as it is flashing quickly about 3-4 times per second like there is some kind of fault. When we unscrewed the panel there was a code flashing from 5.1 - 95 of this means anything? We still have hot water.
Is this the pump return thermistor? Is this relatively easy for a plumber to fix? and roughly how much would it cost for a part?

We have pressed the reset button and the tank is filled with water but its still flashing. Pressing the boost doesn't do anything.

Let me know please or call me on 07793 843982.

Thanks,

Hi
This sound like a: a relay fault or b: the twin store sensor faulty. Check your relays first of any melted plastic or if the relay is passing voltage.
Regards Master Mario at Mario’s Boiler Service