I have the cheapo thermal T-shirts from Primark but they're not very warm and although they're thin enough not to be bulky under clothes they are standard crew neck style and show at the neck of most of my outfits. I also have one nice wool thermal T-shirt which is much warmer, but has the same problem of showing at the neck. Time to upgrade! Can anyone recommend nice (preferably merino wool or wool and silk) thermal layers that have a deep enough scoop neck that they don't show under clothes?