That is unfortunate yes - we did the solar+batteries first and then added heat pump afterwards too, and I think it makes much more sense when you do all of them so they can work together.

I doubt they will withdraw the grant entirely in one go, and I suspect there will be something to replace it even if it's less generous. Installation costs are also coming down too - for me the same install would have cost about 5k less to do today than 4 years ago, before grants are taken into account. There are way more installers now and they are somewhat more commoditised rather than bespoke. Hopefully that trend will continue.