I know exactly where you're coming from!
I had 2 herdwicks - an old ewe and her daughter. Whenever I was gathering my otherwise tame sheep these 2 would always slope off - round the corner, back of a building, behind a bush - whatever. In fact last year they actually avoided getting shorn and I didn't realise till after the shearer had been.
Anyway, the old ewe died last year, but not before she and her daughter had each had another ewe lamb apiece. So now I have 3 of the little treasures!
I don't think you'll ever get them to come like the others, but you never know! I've just been into a field with my sheep to give them some biscuits I'd been donated. Everyone gathered round and even my wary Badger faced ewe tried to climb into my pocket. But not the Herdwick trio. They just stayed at the other end of the field and weren't even interested in what had attracted the others.
They are a totally different mentality to the rest and I don't think even putting a tame sheep in with them would make any difference. I gather mine with the dog when it is essential. But do you really need to catch them at the moment?
Mine actually liked going into a building on their own and I used to put food down for them which the other sheep never discovered. But even then I had to be quick to trap them in there as they would race out if they suspected I was around.
I'm sure you'll find something that tempts them. But in the meantime - treat it as one of the challenges of sheep keeping!