What happens if Queen Sophia Dorothea's proposal to marry her son Frederick of Prussia and her daughter Wilhelmina to Princess Amelia of Great Britain and Prince Frederick of Wales had gone through?
I'm not entirely sure. I've read in several sources that the Austrians were not thrilled at the possibility of said match, and hamstrung it in every way possible. But there's also the mutual antipathy that George II and Friedrich Wilhelm I had for one another (referring to each other as "my brother the drill-sergeant" and FWI referring to GII as "my brother the comedian/play actor" or "my brother the cabbage-head"), so if said match were to take place, perhaps during the lifetime of George I rather.
Also, Amelia always treasured the memory of Friedrich, especially since she was buried wearing a locket with his portrait in that had been sent to her when engaged. Sophie Dorothea also tried to resurrect the match at a latter point by offering Luise Ulrike for the PoW. However, Fritz (if his wife
was the problem) is more likely to have his own kids. AFAIK, part of the reason that he couldn't bring himself to sleep with her was due to her being - in his eyes - an Austrian spy. He wrote to Wilhelmine "there can be no love nor friendship between us. It must simply be "
bonjour, Madame, et bonne chance".
As to getting Wilhelmine to London, she was made to agree to the match with Bayreuth in order to have Fritz released from prison following his escape attempt. So, maybe if that doesn't happen, Bayreuth gets his original intended - her younger sister, Friederike Luise.