I have been employed in financial services for 34 years, and only when the dreaded 'credit scoring' came into existence about 15 years ago did it make my job of arranging mortgages and finance so much more difficult.
Nobody really knows thesecret of credit scriding,,but rst asured, if you have a good job, cleandresoit hostory andsown ytour own house, the younrscore is ususlly goiuto be high.
Any waver from this, as in your missed credit card payments, then the score drops. Yes, it is good that your other card is well maintained, but a chain is only as strong as its weakest link, so most lenders go for the jugular, especially in these harsh borrowing and lending times.
Your record on equifax or experian shows as a row of '0's, if your payments are well maintained. The records only normally go back for 12 months, so if you keep up 12 consecutive months payemnts, then you will have a perfect score, in theory.
You may be bale to apply for finance before the 12 months, as some lenders have lower criteria, but you may not get a typical APR on a Loan or other credit card, so it's worth waiting.
If you are going for a mortgage, most lenders are quite forgiving, especially if your circumstances are exentuating, and it's ony one blip on an otherwise fine credit record, so you shouldn't have a problem. Good Luck!