Agateware Vase

I bought this vase a couple of weeks ago from a very trustworthy lady. I'm not exactly clear on the details but the potter apparently studied with Lucie Rie. I'm not sure if that's possible as the latter trained in Vienna in the 1920s so maybe the potter trained underRie. Anyway, the vendor - whose family apparently had a connection to the potter - said she doesn't know how to spell the potter's name but that she was called Rouge Assanika (I've written that phonically as she pronounced it). It rings absolutely no bells, personally speaking, so anyone else hazard a guess?

The vase, by the way, has an agate ware type decoration under a glossy glaze, over what looks like a terracotta clay. There is an impressed seal on the side within a domed square but it's impossible to read. 16cm tall.