Bunty, two of the lines you've given are incorrect. I think you might have a wrong answer in that corner.
You have to ignore the letters around the edges of the grid - they don't move.
All you know at the outset is that the down entry ends in ..... I N (g) because the diagonal line above the N has two x I, the next letter above these has to be either of the two x S, or the T... then it's a choice between P L(x2) and R.
You have a lot of juggling to do by the time you get to the centre diagonal.
Hope this helps.