Delays occur when you have not lived at your current address for the past 5 years. The CRB have to check every address you have lived at for the past five years, so the more you have moved around, the longer it will take. Same will apply for any 16's or over in your household, as they also need to be CRB checked.
A childminder friend of mine, having just done her accounts, has calculated her income (profit, after expenses) at over £15k. Weather you call this Good Money or not is another thing.
Is there demand in your area for childminders? Try to research as much as you can, so that you have a fair idea of how likely you will be to fill your childcare places. Researching is hard, some starting things to do are getting a list of childminders in your local area from Children's Information Service, doing a postcode search on Ofsted's website to see what childcare facilities exist. Chatting with parents and minders at toddler groups etc.