Large Studio Pottery Jug/Ewer - Maker's Mark Circle in Square

Hi, Could anyone please suggest who might be the maker of this jug? Height 29.5cm. Many thanks

I'm wondering if there's a G in the middle. I don't think it's a mark I've come across before. Looks like a '70s pot

Yes, it looks like there's a small line towards the centre so it could be a G. And it came with a number of pots from the 70s so it probably is from that period. Many thanks again