Wrong. The FA / Broker will arrange a mortgage for the required amount. I have never in 20 years said to someone you want £ 100k why not get £ 140k go on you know it makes sense. What a load of old shit. Still say it enough times and I guess people will believe it.
This is hard concept to understand but some people in Finance actually, now listen carefully, do the best by their client and is not out to stitch them up.
I know you feel you have to stick up for yourself and your fellows, but you seem guilty of what the others are, which is generalising. You are coming across as if you believe every single finance broker is only ever interested in helping their client, profits be damned! Others here are suggesting they're all out for whatever they can, screw the customer as hard as they can!
Truth is, some and some. Like most things; car dealers are out to make a profit and some put that ahead of their customers, electric goods you want the £300 TV, why not go for the £400 one, and we'll offer you 3 months interest free credit, etc.
I'm sure you do your best by your customers, US, but there will be people in your line of work who put their profits first, either because they are greedy, or because they are weak willed and work for a greedy company.