Which Mono Kitchen Mixer Tap for low Pressure System?

[Lancastrian]

I need to source a tap which is suitable for a low pressure system - we have a condensing boiler so the water pressure is low because I am told it is gravity fed
The plumber left it to me to source a tap and as I have little knowledge of plumbing I bought a Classic Mono sink Mixer in Antique Bronze made by Cassellei to replace the previous one on which the tap thread was knackered
I understand now that the one we bought is for high pressure systems
The one we bought only produces hot water at a very weak flow
I will try to attach a Photo of old one - we would like something similar to the old one which is also compatible with a low pressure system - the old one gave a very strong stream of hot and cold
I presume that we need one with a wider hose etc
Any advice would be appreciated