Effect of credit cards on credit scores

cjcookie6

I have had a credit card with Natwest for about 5 years but, as it is a student account, it will be closed in about 6 months time. About 6 months ago I got a second credit card with them with a credit limit of 4x my monthly income. I know longer relationships are seen as good for future lenders so I was wondering if anyone has any thoughts on the effect that losing this account will have on my credit report? In a year or so I will be looking for a mortgage and want to know if it best to close the credit card now, so that any negative effects will be lessened by the time I come to get a mortgage, or whether to keep it open until it is closed for me?

Also, how much credit is too much credit on a credit card? I feel that 4x my income is probably too much but if I get it reduced what would be a sensible amount? I never use anywhere near the limit and the card is paid off in full every month so I don't need this high amount but I assume there is a benefit to having a reasonable amount of credit available? I am thinking of asking for the credit amount to be reduced as I noticed that my credit score has fallen since this card opened so I wondered if this was because I had too much available credit?

Sorry for the long post, any advice would be welcome!

Nebulous2

Why does it need to be closed? Banks will convert student accounts into normal accounts - with the loss of some of the benefits.

That isn't what most people regard as four times your income. When people refer to that they are usually referring to annual income, not monthly. I have had in excess of twice my annual income in available credit on cards in the past.