Small replacement boiler choice

Hello, I wonder if anybody can help here. My daughter is seeking to replace a 25 year Baxi boiler in her 2-bed, 5 rad, 2nd floor flat. Heating reqirement is only around 6kW plus dhw. She intends to replace with another open vent boiler in the same kitchen location – under the worktop.
Space is therefore limited to about 875 mm vertically.
Can anybody suggest a suitable boiler?
If manufacturers’ instructions regarding clearances are followed few boilers would appear to fit.
n power have quoted for a Glowworm Flexicom which can have a direct rear flue which saves space. Another has suggested a Potterton.

One other thing, the existing radiators are aluminium. Is it still worthwhile to add a Magnaclean?

Thanks for anybody who can advise.

Sorry can't help with boiler selection but aluminium rads + copper pipework + (probable) SS heat exchanger = Magnaclean no point!

Make sure you dose it up with a corrosion inhibitor suitable for aluminium.

Thanks Tipper. Well that's what I expected but 2 companies have included Magnacleans in their quotes. I suppose they did not notice that the rads were aluminium - they do look smaller than you would expect - no doubt due to superior conductivity of aluminium over steel.

Now can anybody suggest a small reliable boiler that will fit under a kitchen worktop. Trouble is its not just the fitting but giving access for servicing in the years to come.

Intergas HRE combe 24/18 this boiler can be used as a heat only boiler on either open vent or sealed system. the height is 590mm width 450mm depth 240mm. the total height including the flue elbow and pipe connections is approx 875mm. so you might struggle with pipe work. check with Intergas they will give you correct sizes.

Thanks for the info. It may do the job. I will try to contact the company for further details.