System boiler suggestions smallest size possible

[Anstiss Ltd]

Im currently renovating my bungalow with loft conversion and dormer.

I currently have no boiler,
so no central heating or running hot water etc. (Hot water from a electric heater and shower heating from storage heaters)

I will be installing a boiler, I'm very limited on space.

Now my thoughts are a horizontal sealed cylinder 200ltr in the eaves.

And a system boiler in a storage cupboard the cylinder and boiler will be about 3meters apart

The whole bungalow is underfloor heated up stairs and down 8 rooms and hallway/landing in total.

I want to run a shower and a shower/bath

I want to minimise the impact on the cupboard only real place for boiler unless I can fit it also under eaves.

I need suggestions for the smallest in dimensions boiler I can fit.

Thank you
Regards Thomas

(I usually do small handyman sorta jobs with the odd renovation, all been simple update existing and sell on houses. but this is my biggest project to date it's my own house that I'll live in)

Edit**
Most plumbers in my area are saying combi (not with two showers) or are just trying to throw in what's easy rather than what's best for the space

Edit* X2
I've replaced the original lead pipe not tested flow yet but it's the best I've had in any house I've lived

 

[muggles]

How much space do you actually have available?

 

[Anstiss Ltd]

Not 100 percent on dimensions as the loft conversion isn't done yet so full dimensions are not known

 

[Anstiss Ltd]

Will try and work it out from drawings it's in the roof slope so unsure on the height