Have narrowed my choice of combi wall hung boiler down to
the Vaillant EcoTec plus 837 or the WB Greenstar 35CDI.

Any helpful comments to assist with making the final decision ?

Thanks

Robert

House spec is:
large 3 beds, 3 floor midterrace, solid rubble walled (ie poor
insulation) house. with 1 bathroom and 1 ensuite shower but little
simultaneous use.
Present boiler Ideal Mexico RS65 okay for CH & HW.
Robert