@Shobeck
I’m not at home and haven’t been able to re-add my battery after upgrading the app (the battery/inverter is in my IoT VLAN, so it can’t be detected by the app which I’m assuming is only scanning the VPN range).

What I’ve done is sign up for Axle as mentioned in the GivEnergy email this morning. I found a referral code on YouTube so I’ve already got £25 credited to my account, they are currently guaranteeing a minimum of £10 per month for buying electricity from your battery at peak times (£1 per kWh, in addition to the 12p I currently get by exporting excess solar and battery capacity to Octopus). As a side benefit, that also gets me the GivEnergy Premium subscription for free, so I’ve got all the old functionality back.