if ive been given set rules on a orchestral score to
"3333 – 4331 – harp – pno – tmp+3 – strings"
what do the numbers mean for instruments?

I would assume that means:

3 Flutes
3 Oboes
3 Clarinets
3 Bassooons

4 French Horns
3 Trumpets
3 Trombones
1 (Tuba?...)

Tmp + 3 = Timpani + 3 other percussionists
Strings = Violin I, II; Viola; Cello; Contrabass

Best guess I can make.

sounds about right thanks = )!!