Andy,
I've had good luck with coated nylon toe clip covers on cold days, and just recently invested in some Louis Garneau thin (3mm) neoprene over-shoe booties (only USD$15 on sale...never could afford them before). Both can be used at once, and I think my feet will be warm this winter -- Yay! Previously, I had used plastic bags in the toes of my shoes to break the wind, which helped greatly. Remember, I'm probably the last old roadie in the world using Detto Pietro Article 74 cleated cycling shoes...the kind with many large holes punched in the leather so they *will* breathe nicely on all days -- in torrid heat and sub-freezing cold! Hopefully, the shoes and socks will stay dry when it pours rain, my main reason for getting them (leather shoes take forever to dry on-tour and want to come apart if ridden wet).
So sorry the SealSkinz didn't do the job for you. They didn't for jags, either, but seem to be the ideal solution for others. It may be they are just one of those things that work on an individual basis. Glad you have an alternative in the wet-suit socks.
Thanks for the report; one more data point that will help others.
All the best,
Dan. (...who wouldn't mind trying some someday, but is beginning to have report-based doubts about shelling out for them)