There is no way the academic needs in terms of support needed are in any way on a par with a child with "any SN".
I have 1 of each, I work with both of them at home, and its completely without comparison. One has an unsupported attention span of seconds. If I want him to match words and pictures I have to say "look at the word" before he can even do that. Even though 3 of us have been workiing on this for weeks we're still not sure whether or not he can recognise words. He cannot play unsupported let alone work unsupported. He is in a class of 6 with 5 members of staff present every time I've been in there (which is quite a lot recently). Sometimes one child requres 2 members of staff to complete an activity. The last lesson I attended involved 2 students & 3 adults.
Children who are G&T do not remotely need that level of support. I can direct ds2 from afar- "hey ds2 why do you do x, y, z" I only have to guide him I don't have to sit next to him to stop him standing up and running off, I don't have to physically prompt him to teach him something, I don;t even have to be sat next to him. Stretching ds2 should not require extra funding - in ds1's case it is absolutely essential.