DIY Conservatory Roof Insulation

[Jooolz1]

Looking for opinions on doing a DIY insulated roof on our south facing conservatory. We only bought the house earlier this year. We have constantly used the conservatory since May and we eat in there every night. It has been very hot on warm sunny days but we've been outside in the garden then anyway. We want to use it over winter too though as we love it.
My DP is a joiner and plans to put insulation under our current poly roof then internally clad under that. Some of the windows need replacing as they are shot. He will pull up the floor, insulate underneath and put new laminate on top. We have an all round cavity dwarf wall. We also intend to put a heater/cooler fan in or similar. Eventually we will put a rubber roof on instead of the poly one or maybe just put it over the top.
Any flaws on our plans?

Exactly what we did. So insulted the ceiling and then boarded over. We also boarded inside and outside of all the glass apart from one end. This was also insulated. It was a cheap work around but has been ok. The only thing I will say is that it can get damp so do heat it when you can.

Thanks we will do. When we moved in the blinds were mouldy black because last owners just didn't use it as was cold in winter.