If you have a credit card with PPI (payment protection insurance) or you have had a loan protected with PPI, you may have been miss sold the insurance (or not sold it at all, it may just have been put on automatically by the bank). If that is the case, it is worth putting in a claim.
I'm generally a bit apathetic about these things, but a few (5/6) years ago I broke through my apathy and phoned the bank to cancel the PPI on my credit card. Some months later they decided to issue some shiny new cards and replace my old one and they put the PPI back on. Again, my apathy just allowed them to do this but it did sit and niggle and that niggle festered until in a fit of activity that took all of 10 minutes, I tracked down their PPI complaints form, filled it in and popped it in the post.
I thought I would be entitled to some money back because I had definitely asked for PPI to be cancelled (but even if you didn't - you may still have been miss sold the insurance), but since I pay off my card pretty regularly (mostly every month but not quite always) I assumed I would get back about fifty quid. I just got a letter with an offer of settlement that's a very tidy sum indeed.
Banks have had to set aside billions to deal with PPI claims because the 'miss selling' of PPI was rampant. A huge amount of that set aside remains unclaimed. There are plenty of firms out there offering to deal with PPI claims (for a hefty cut) but actually making a claim is easy and that 30% could be a serious dollop of cash. If you are like me and a bit apathetic about these things (I just hate dealing with banks) you may have been put off or you may not think it will be worthwhile. All I can say is DO IT TODAY!
I did something of this ilk a few years back relating to unproportionate profit on bank charges in relation to actual cost (unfair profiteering).
Requested my entire statement history for the last 6 years and highlighted every bank charge they ever levied. In my younger days I was pretty bad with cash and had a lot of these at £30 a time. I sent of a simple letter detailing the law around the situation and received a settlement into my account of almost £2k.... Albeit money I had already paid in one way or other, it was a very useful return.
I shall also be looking a the PPI on my credit card and forwarding my concerns to said company....
EDIT: As mentioned above this is a simple process, DO NOT use PPI claims companies they are just greedy. If there was little or nothing in it for them, would they really go to the trouble of calling you at the most inopportune times?
I've just had £2650 from HSBC and Barclaycard from miss sold PPI. Took me 10 minutes to make a phone call, then fill the ombudsman form when it came in the post a few weeks later. Both paid me just after 8 weeks from the initial complaint. Very easy to do!