There was a recent post similar to this which was concerned with the fate of the Circassians. The Circassians were allies of the British and French and in the aftermath of the war the Russians continued to invade and displace the Circassians. Genocide and the topic of genocide is somewhat taboo on this forum however I think it’s inportant to acknowledge that this is what happened. The Circassians formerly pleaded for further British intervention - a letter now famous/infamous was sent to Queen Victoria - I’ll upload a picture or link later. Many maybe millions of Circassians now live across the globe - a forgotten diaspora in many respects.
However the pertinent question would be under what circumstances would Britain have ensured their survival. Certainly at the time in Britain there was a swell of public sympathy for the plight of their allies.
To be fair the Circassian genocide is probably one of the least controversial genocides around—mostly because there’s no one to “defend” it like with the Armenian genocide and the Holocaust.
I could see Britain offering part of Crimea to the Circassians if they won the war at least.
Considering the timeframe, the vast majority of the Circassians were still in their homeland with the process of total expulsion having barely begun. Would it not make more sense, especially given that establishing states between the Ottomans and Russians as a solution to their conflicting desires and security concerns seems to be the evolving consensus by the powers-that-be, to re-establish the region rather than transfer the locals to the Crimea (Which, remember, has the Tartars with a claim to it?). They were also allied peoples to the Ottomans, who provided supply and aid during the Russian conquest of the region and formerly owned several coastal fortresses, who would also support this proposal. Even IOTL, they'd become the primary destination for the refugee population.