Most of the couples have had a straight swap from latin to ballroom and vice versa. However due to numbers that would have meant 5 American Smooths and only 3 Sambas so one American Smooth couple had to move over to Latin. That couple is obviously Louisa and Vincent.
Therefore:
Samba - Ray and Camilla, Emma and Darren, Peter and Erin, Louisa and Vincent
American Smooth - Carol and Matt, Mark and Karen, Claire and brendan, Matt and Lilia.