horsemadmummy - I have had the same with Swaledale first timers, and not just once or twice. Usually it has resolved after a day or two, especially where the ewe seems to love the lamb. Where she gets cross with the lamb or even seems to actively dislike it it can take longer - once I persevered for a week before the ewe capitulated. I have only occasionally given up, usually because I simply can't devote the amount of time to a single couple in a busy lambing period. (I have been known to tie the ewe up with a halter, though never to leave the shed with anyone so tied up. I often think about making an 'adopter' pen but have never quite gotten around to it...)
I wonder whether by now you would be able to get the lamb to suckle directly, rather than having still to milk mum and bottle baby; it would reduce your workload a little and help to get the ewe used to the feeling.
The other thing I sometimes do is have a woman-to-ewe conversation in which I explain that the sheep are not pets and that freeloaders don't get to stay on the farm. The word "chops" is sometimes used in this conversation. You would be amazed how many times it has worked...
