Plus size, outsize, big and tall mens boxer shorts, vests, underpants and briefs.

Big Tee Shirt - a good value UK outsize retailer, supplies inexpensive underwear for the bigger person to size 8xl (66" boxers, briefs & vests) and up to 13xl (92" chest) in polo shirts. For European orders the delivery costs are calculated by weight and are added at the checkout.

Big Tall Order sell Metaphor underwear to size 5xl and Jockey boxers, vests and pants to 6xl. Signed for P&P is £14.95..

Big Papas
Big Papas supersize boxers and underpants in sizes 8XL 9XL and 10XL. Made for heavy men up to 86" hips. EU postage £4.45

Chums is a niche direct mail order company with traditional underwear for men aged 55 years plus. They stock hard to find high waisted underpants and stock waist sizes up to 54" boxers and 58" vests. Thermals too.
You MUST contact them before ordering for EU delivery, to check delivery costs.