vintage clothes in good condition. where should I donate them for maximum reward to charity?

Look for a Vintage Clothing shop, they might buy them from you. Or go talk to local charities to see what they actually do. When I volunteered in an Oxfam shop we had experts to assess things that might be valuable, we put on one side anything possible and they got sold at auctions.

Oxfam have an online charity shop where they sell, among other items, vintage clothes

Do you have to post photos or can you just take them to Oxfam? Marmight

Save the Children has a chain of upmarket charity shops started by Mary Portas I think they’re called Mary’s Giving Shops , might be worth checking them out.

To think that I bagged up 20 + bags of 1930's/40's clothes to end up on the tip years ago which belonged to my late SiL ! Heavy beaded dresses, furs, and general " cruise-wear ". Ankle-strap shoes handbags. I daren't think about it, though I don't expect it would have been appreciated in the 80's and there weren't the charity shops back then as now.

The Red Cross have several vintage shops scattered across the country . They also sell vintage stuff on eBay.
Have a look here

Oh EllanVannin I feel for you. I would have done the same .
Yet I guess this adds to the scarcity value so never mind.

Someone anonymously gave a load of designer clothing to a charity shop in Tumbridge Wells. I mean really posh stuff. They had no trouble recognising it’s value?

I also think the charity shops are experts at this but worth asking before you donate.

Goodness my daughter in law would love what you are describing, she has many vintage Laura Ashley dresses. (Do DM me if you want to sell any, I’d put them aside for her Christmas present!) recommendations for specialises charity shops, Shooting Star Children's Hospices Charity Shop, they have stores that specialise in designer vintage, email them and let them know what you are donating.

salvation army are the fashion designer ,we know what labels are what AND we have a list that tells us..we just sold vintage dresses at £80 each /wedding dresses at £150.. we love vintage.

Oxfam