Recommendations for double glazed aluminium windows in crittal style in NW London

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I’m struggling to find an aluminium window company that can reliably get me a quote for new double glazed windows for a whole house. I need about 18 units in all. The system I like is the aluminium Heritage System. 

Two months ago I requested quotes from 3 different companies. Despite chasing, only one of them (Jennyfields) have got back to me, but even getting edits made to that quote is like drawing water from a stone. I imagine the pandemic has put a spanner in the works for some of these companies, but it is still crazy that I am offering to spend tens of thousands on a big aspect of my project and suppliers don’t seem bothered. When the pre-sale service is this slow, it really didn’t fill Me with confidence. Any recommendations, greatly appreciated. I’m in NW London.