23 across - TV programme based on George Orwell creation
28 across - Maths term
5 down - Landmark occasion
13 down - BBC sorts station
27 down -Version of football
Just had another look. Putting the symbol for times rather than a number at the end of 13 down would make the middle part of the grid + 28 across read much more like a sum which would produce the required result. Away now for a very long weekend and won't look at any crosswords until Wednesday, not even if I get withdrawal symptoms.