eBay?
I searched for "landrover wheel brace" and got 32 matches.
Personally I wouldn't bother trying to get an original one, they're almost unbelievably soft. Mine is now banana shaped.
I had mine replaced at my local LR specialist and they used the very technical technique of putting a drill through them! Thankfully he'd stuck a trolley jack under the tow bar so it didn't land on the floor!
I have Saharas and I'd agree, they're good but not amazing in mud. I also don't like the handling on the road, it's very vague. There's a wee bit of road noise but it's not too bad.
Second recommendation for Gemm4x4 in Larbert. They're good guys who know their stuff.
I've no connection other than being a satisfied customer.
Hope this helps
Gary