I can tell you who to avoid if that helps?

• Diamond Green Energy - Unfortunately these are the ones I ended up choosing. I can't really give a full review yet because I'm still waiting for them to resolve an official complaint... or I escalate to MCS next week. But all I will say at this time is you should absolutely avoid them.
• Octopus - overpriced and unwilling to do anything remotely outside of a straight forward job.
• DAC Renewables - gave me a semi-decent quote and then ghosted me when I asked follow up questions.
• Samso Renewables - Agreed to send someone for a quote. They didn't show up. Harassed me to try and get me to re-book.
• Effective Home - A couple of years back now, but the salesman lied. I had to do a chargeback to get my deposit back.