Saying hello - and any advice on consumption and heat pumps?

My name is Kirsten and I've just joined Whitelaw Brae. I live in Birmingham.
Also, we're ditching our 25+ year old, inefficient gas boiler for a heat pump in June. I had signed up for 2700 kWh but this will likely change as we switch from gas/electric to completely electric. Does anyone here have a heat pump, and what's the typical electricity consumption? I'm considering signing up for more before the window closes, but I'm not sure for how much, and also, the share offer window closes before we get our heat pump installed (w/c 17 June) so I'm not sure how we can evidence higher consumption.