Artificer, in the last 6 months I have purchased 1 Harris Tweed kilt jacket and two Tweed kilt jackets on ebay. One was a 44R and two were 46R. None were listed under tweed kilt jackets and I got them all for under 80.00GBP each.
I search under Harris Tweed jackets, Scottish jackets, Highland Jackets, Tweed jackets and nurmerous other combinations

As others have said you just have to have have a varied search parameter

Good Hunting