Covid booster jab

I’ve had 2 AstraZeneca vaccines this year and now due my booster next weekend. Can anyone tell me what to expect in terms of vaccine type?
Will I get a 3rd shot of AstraZeneca or a different vaccine at a lesser dose?
I tried calling the helpline and the girl had no idea. She just said I should ask when I go for vaccine. Not very helpful. Thought I would ask you guys.
Many thanks

As far as I know everyone is getting either the Pfizer or the Moderna as a booster. I don’t think Astra Zeneca is being used for boosters.