To the first part of your question - I have no idea. However, if an idea has been patented, or a patent applied for, the UK Patent Office will have a record.
As for the second part, if you think you have an idea that is commercially viable, then you need to look for a company that produces something similar to your invention (i.e. if it's a part for a car, then a manufacturer of car parts) and would have the equipment to produce it. When you approach anyone, do not give details until they have signed a confidentiality agreement. Then, if they are interested, you can hammer out terms. They would depend on how much the manufacturer would need to invest, whether they buy the idea outright from you, and any number of factors which cannot be defined without knowing all the facts.