Hello, I'm a newbie here, and also to the world of keeping sheep, so would be very grateful for some help with an bottle fed lamb. Brief background - we have a 2.5 acre paddock behind our house with plenty of good grass and some mature trees. 2 years ago we acquired 4 young alpaca wethers for their fleece, then 2 months ago we bought 2 x 3month old dorper ewes for breeding. We weren't sure how the alpacas would feel about having their nice herd encroached on so we chose the bolshiest ewes from the breeder, put them straight in with the alpacas and they've got on fine.
5 weeks ago our neigbour's sheep gave birth to triplets right by our fence. Two of them were up and off, the third lamb couldn't stand and got left in the ditch covered in flies. You've guessed it, with the neighbour's blessing I acquired a lamb. She didn't get much colostrum, weighed about 2kg and couldn't stand for the first three days. I expected her to die but she took the bottle ok (I'm so much of an amateur I didn't even realise sheep need different teats - she's had a normal baby's teat the whole way through) and the last 5 weeks has been like having a newborn baby in the house. It was the end of winter and quite cold (I'm in Perth, no, the other one - Western Australia) so I put her in a nappy and a babygro to keep warm and the long and the short is that although she's still only just on 7kg she's eating hay and a few pellets and doing well. She sits under my desk by day and sleeps by the bed at night.
But she can't stay in the house forever and my attempts to get her in the paddock with the others are not going well. Inevitably perhaps I've made the mistake of letting her really see me as mum, even my husband won't really do. The two ewes generally completely ignore her, and she them, though when I've tried to push her towards them they stamp their feet and head butt her - not promising. The alpacas are great up to a point, they're very gentle, but as she doesn't want to be part of their flock they move round the paddock and leave her behind. I've been leaving her out there for the mornings, and she literally runs up and down the fence line behind the house crying for 4 solid hours till all I can hear are heartbreaking croaky sore-throated little bleats. I need to get her out there all day to start acclimatising to the heat - I'm not expecting her to be fully weaned till Christmas, by which time it'll be

in the 40s (C).
If anyone's been in this situation, or has advice I'd be really grateful. All the advice on google is to put the orphan in with a couple of gentle ewes (!) and their lambs so should I see if I can get another lamb so they can both go in the paddock together (though I fear that might just be doubling my current problem!), do I just have to harden my heart and hope she fits in eventually or would she be better off in a new home altogether? Thanks in advance for any help!