To ask for restaurant recommendations in Wantage/Abingdon/Wallingford triangle?

[Iused2BanOptimist]

It's a bit last minute as it is my Mother's 90th in a week. Elder DS has organised a weekend extravaganza in London the week after which I am about but I don't want to go on about that.
Anyway I thought it would be mean if no one sees her the actual weekend of her actual birthday and offered to take her for lunch on Sunday, and plan to bake a cake. She is pleased but has now asked if I can invite my Aunt. So I'm doing a last minute change of plan as I want somewhere not too far for my aunt to drive. She lives in Henley. My Mum in Lechlade.
I'm looking for somewhere fairly smart, maybe a hotel with a decent restaurant and excellent service but not massively expensive. No ethnic food please. Her favourite sort of menus are Brasserie Blanc type of thing.
Any recommendations please?

Shoulder of Mutton if it’s not too bonkers a drive, really nice. Great food.

The Mole Inn in Toot Baldon is very nice.

Oh. DH suggested Mole Inn. I'll have another look. I thought it was a bit further north than I hoped.

Try Home Sweet Home in Roke by Wallingford

Which Shoulder of Mutton? The one in Wantage looks a bit "pubby" for Mum.

You could try the Cosener’s House in Abingdon for Sunday lunch

I'll have a look at suggestions and get back. Thank you all.

The Waterfront in Benson.