I also like to lamb over winter and though not small like the primitives, Dorset Down. They tup for November quite easily (I found this out by accident as I prefer December!) I loved my Dorset Downs, pure girls and tup. Mine were quiet so very laid back! In 2004 I purchased Shetlands and put my Dorset tup on them for lambing the next year. Now, the Shetlands didn't lamb until March, but their offsprings, had the early gene ability meaning they could and did lamb in December. If you want natural winter lambing then you need a sheep that can do it or a % that can do it.
Due to electric costs escalating my sheep are running with a tup now, but they are Wiltshire Horn and a Dorset Down Tup so aiming for February. My sheds are all LED lights but they still cost to light!
I have lambed bottle reared and some have been brilliant mums, they were cades so Suffolk X mules, Texel x mules, BUT I have also noticed, compared to my Dorsets and my homeborn X's, they didn't seem to last. By age 5 (to me young) I could honestly say they were knackered! One started having lambing issues age 4, (had trouble passing twins) kept as liked her, disaster and vet bill the following year so she was culled, another just didn't want to lamb so brother in law for 3 years running had to pull them, he said everything perfect, just idle, she culled, another could lamb anything and had multiples each year but had a dead tit year 3 I think, but kept as she was a really nice ewe (that and it gets annoying and at time emotional to part with nice ewes!)
But my Dorsets lambed without issues until they were 8 or 9 and were only culled when they started to have problems. Others were sold on with lambs or in lamb as I was downsizing to the Shetland X's due to the size (ease) of handling them.
I'm very partial to Shetlands, not for the wool, just their characters, get the right ones and they make me smile! Have actually bought some in again but am going to keep the offspring pure this time, (for now!) I wanted a black sheep, got 2 now and some brown to go with my pure white Wiltshires!