I got stuck in the top left of the grid, so would appreciate help with this clue:-
1 across - "Radiant Internet user's letter" (8) I have the seventh
letter as "V", and the third one may well be "U", therefore
--U---V- may well be a contribution.
Your V is correct but your U isn't (should be I) - definition is "radiant" and it's the usual single letter that precedes things on the internet followed by a 7 letter "letter" - if you see what I mean:-)