Large Swimming Suits for Women

A few months back my wife started swimming lessons. It turns out, she's pretty good.

She already has one suit we purchased in the UK, but needs a couple more as she is going to the pool two or three times a week.

The major problem is, she is size 40 .. Speedo at supersports only stock unto 38.

Does anyone know of a specialist sports shop where she might be lucky ?

Shop assistants try to push her in the direction of pink flowers and those skirt-type affairs for jumping around at the beach, but she wants a real one piece not a fashion item intended for occasional use.