A further update for those who kindly gave me advice on this. After lots of research, chatting to install companies, other churches and a generous donation from a member of the church who recently passed, I settled on using a local company TSPro who have done loads of church installs and both my boys used to work for on Saturdays back when they were (much!) younger.
Going in this week is a system based around an A&H Qu16 desk, A&H stage box, EV speakers, Sennheiser wireless mics plus a three screen video system with wireless streaming. I’m adding some gear I was able to source more cheaply from Thomann - e835 mics, K&M stands, Alto powered monitors and a few other bits and pieces. Ready for a try out next Sunday, two days before I start my first round of chemo so hopefully all works well if I’m not able to be around quite as much. Hugely impressed by what I’ve seen of the Qu16 so far - easy to set and recall scenes, run via an iPad - lots for me to learn. We’ve also been able to afford (thanks to the bequest) to replace all the old wooden chairs with fabric padded ones which I think will help with the acoustics.