Boilermate causing issues with boiler?

Hello
Discovered this useful site after getting no where with local plumbers, boiler specialists, etc locally - hoping someone on here may have some useful advice! Long story unfortunately but please stick with it!

I live in a property built in 2005 with a boiler mate 2000 and a glow worm boiler. Our boiler had been working fine since we moved in to the property 3 yrs ago. We updated the bathroom in the property in March and after that work was completed we had intermittent hot water and the boiler made a hell of a racket when in use. We had a Glowworm engineer visit the property who advised that the heat exchanger was knackered, he advised that he expected when our plumber drained the system to fit the new towel rail etc in our bathroom that some residue had got in to the heat exchanger and damaged it etc.

Glowworm replaced the heat exchanger and all was fine. We went away on holiday in May and on our return when using hot water the boiler began making odd noises again, mainly whistling when hot water was in use. This whistling then developed over time to resemble very similar noises to those we experienced after the bathroom had been fitted, similar to an aeroplane passing over the house or the noise a kettle makes as it reaches boiling point.

We called Glowworm back and of course while the engineer was onsite bloody boiler made no noise, he adjusted something behind the front panel of the boiler and the noise went away again for a few weeks.

Noise has now returned again and another Glow worm engineer has visited my property however this one has said there is nothing wrong with the boiler and is blaming our Boilermate 2000 suggesting that the heat exchanger in that is at fault and is causing the boiler to make the noises it is. He has recommended we carry out a power flush of our system and get a Boilermate service carried out to ensure there are no faults with the boiler mate.

Does it sound like the Boilermate could be the cause of my issue - will power flushing help or should I get a service done by Gledhill? I don't really want to pay out for both if I can avoid it so any advice would be welcome.

Thanks in advance

Where is the top tank / F & E tank located?
How high is the towel rail from the floor?
Mike

It's located on a shelf above the boiler mate approx 76 inches from top of the tank to the floor. The top of the towel rail is approx 72 inches from the floor.

Check your book.
BUT
The highest the towel rails can be are.
200 mm below the water level in the F & E tank.
This could be causing your problems.
Raise the F & E tank.
Mike

And you must not power flush the system with the unit connected.
Mike