The right settings

I’ve recently had solar panels and home battery installed. My simpleton view was… during the day we’d feed off solar and battery, at night we’d charge the battery (and car). Obviously any surplus would be exported back to the grid. We are with Octopus and are on the intelligent go tariff for EV. 7.5p night time rate. But I have no idea if my system is working or giving the me the best results. The reason for this post is I just noticed that my battery is currently taking from the grid, before the cheap tariff! This is not what I expected. What is the best way to set up the system?

I think if you are on an intelligent tariff, then Octo are doing what they think is best for you and the grid. If there is surplus energy in the grid, they may be pushing it into your battery at a very low cost (may be even paying you to take it ?).
You might have to look at some sort of tariff tracker to work out what is going on for you in your circumstances.
This is what I see on my Octo web page. I am on Flux

Cejr79 Welcome to the forum.
One possible reason for charging from grid is that the battery hit the bottom reserve: I think it does that as a sort of self-protection, since running below the minimum voltage can damage the cells

Perhaps post a daily chart showing solar, grid, consumption, etc from the portal?
(Some choose to obscure serial number, for security.)

DD pointless trivia but it's based on a simple timer when it gets too low and force charges:
https://github.com/hoggyhoggy/givenergy-modbus-async/blob/08283f8a85fad009b020d9a892085cf5515997da/givenergy_modbus/model/inverter.py#L282

SteveCook I think if you are on an intelligent tariff, then Octo are doing what they think is best for you and the grid. If there is surplus energy in the grid, they may be pushing it into your battery at a very low cost (may be even paying you to take it ?).

Not sure IOG works quite like that. You tell octopus when you need your car, and they choose which half-hour slots to use. But the price is fixed - if wholesale prices are -ve, they keep that for themselves. It's only really Agile that discounts prices on windy days. Unless you're in a region that offers power ups, perhaps.

I'm at home most days, and would be happy to give octopus the freedom to add 10kWh by Tuesday, say, but it doesn't yet have that level of configurability

Cejr79 My simpleton view was… during the day we’d feed off solar and battery, at night we’d charge the battery (and car). Obviously any surplus would be exported back to the grid.

You can choose to actively export battery contents to grid at the end of the day, then recharge overnight. I choose to export most solar directly, rather than have it go through the battery, saving some of the round-trip losses.