Best shapewear for 18/20 big arse

[DayOldCheesecake]

hello, I'm in need of shapewear to control "powerful" thighs & arse and no tummy. Ideally I'd like it up to the bra or even with cups (38GG) as I'd like to be as smooth as possible.

Spanx? Gok wan? Elusive other brand?

I'm an 18/20 and i can say that something from under bra to knee length is the way forward!
The ones i wear come from House of Fraser. Can't remember which Brand they are although i can recommend lycra based material. Avoid Trinny and Susannah if they still make them as they are very nylony, and tend to stick to what you're wearing. Also avoid anything with a thicker waistband that is supposed to define your waist, all that did for me was push wobbly bits further down south and did not flatten anything!