Advice for new system

Hi everyone - I was hoping to get some advice for refitting a new retail showroom. The existing showroom (180m2 ground and 120m2 first with an airwell) has 1 Daikin wall mounted system and 1 ceiling cassette heat pump, both about 12 years old. All units are on the ground floor and the showroom is north facing so never really gets too warm in the summer. In the winter we time the units to get sufficient heating throughout the building. Due to planned extensive refurb work, the wall mount system (running R407a (banned refrigerant)) needs to be moved. The heat pump works fine and is a permitted refrigerant.

I have had a few quotes and everyone has recommended scrapping the banned unit. Some have recommended scrapping both units while others say its old but works so best to use it while it lasts.

I have had quotes for removal of existing systems and installing new ones and the recommendations are varied. 4 * 6kw internal/external systems from Daikin, Mitsubishi/Fujitsu, 2 * 12kW external and 4 internal units, and 3 new internal/external units plus reusing the heat pump. Where similar proposals have been put forward, the prices are in the same ballpark. All units are to be sited on the ground floor only.

Needless to say, I am confused about the way forward. I must add that units with ECA are a must as a lot of this cost is an unforeseen cost so it helps to offset it to the greatest extent possible.

Any recommendations are gratefully received.