credit score UNITED KINGDOM ONLY PLEASE?

[TTC#1 1m/c]

applied for a new look card a while ago, ive worked since i was 13 i have a mortgage, a good income between us with child tax credits ect.... never missed a payment on anything... im not great but not bad, anyway i got declined, my friend who is on benefits got accepted even tho she got thousands and thousands of debt, so after a while i ended up applying for a few more things as we had got married and bought a house, i was very worried about my credit file wondering how it was so paid to get a copy of my credit report, anyway out of 500, 500 being excellent, my score is 417 which is good, but when i applied again it said my score wasnt good enough??? can anyone help me understand, my file is saying im a good candidate but creditors are saying im not???

Credit search was by equifax,, -299 v.poor, 300-349 poor 350-399 fair,400-449-good 450-500 excellent.
im in the uk so please no answers from america as you use a different system that us.