You're in the same boat as a lot of potential pilots. There is no magic answer (unless you have rich relatives who can afford to loan you the cash).
I'd love to be corrected; but I don't think there are any unsecured loans in the UK for £46,000. You're going to need to find another option.
I'm speaking as a former modular stude, who spread his training over a number of years, borrowed from parents, worked, saved, and so on to complete training. No loans.
The jobs market can be extremely unforgiving; whilst I know of people I trained with who did modular, and did very well (recently starting at BA, Virgin, to name two) others have not managed to get a job in five years post training.
Whatever you do, do not bet the farm on getting a job straight out of training. There's a good chance you'll have to wait some time before getting into the cockpit of something. I can't stress that enough!