One of my sfflk/txl cross ewes rejected her lambs for two years in a row, but both times I penned the lambs in a seprate pen next to mum and went down every two hours to hold them onto her. She butted them away, but you quickly get the hang of holding the ewe with your knees against the side of the pen and helping the lamb to suckle. After a week of this she was happy to have her lambs in with her and has proved to be a very good mum. But it meant that once she started lambing I stayed with her until she lambed (second time during the night...) . I also made sure lambs had their colostrum plus some artificial colostrum/milked out some.
I did not go to feed every two hours during the night, just gave the lambs a belly full of colostrum/goatsmilk through a tube and then a 5 am feed from mum again. They were actually really strong lambs.
This last year she lambed in the field during the day (I was watching though) and let the lambs suckle immediately... so really my only advice would be supervise her and if you have any inkling that she may start to lamb stay with her and watch. Only intervene if absolutely necessary and have a couple of pens (one with a heat lamp) ready if needed. if she starts to butt the lambs separate them and force her to let the lambs suckle. She can sniff them through the pen. Mothering instinct should kick in within a few days. And I would keep auntie well away if possible.
However I have to admit that I had a wisper into her ear just before lambing - the words freezer and curry were mentioned .... it definitely did the trick...
PS.: Her daughter lambed this year for the first time - long labour, lamb No1 came with the head only, but was quickly removed by bringing one leg forward. Lamb No2 just shot out... but no issues re suckling, she was a good mum. Maybe not an inherited trait then...