Normal maths for spray work is £50-£250 per full panel depending on prep needed. A front bumper getting a good quality paint job needs removing, sanding, filling in of deeper chips, priming,sanding, colour coat, sanding, top/clear coat, sanding, buffing and polishing if done properly.
Or, wipe over with some heavy duty solvent, quick rub with scotch pad, base colour, top coat, machine polish if its done on the cheap.
A full front end, bumper, wings, bonnet blended into doors will cost about £600-£800 done really well. A full car respray is £2000 done well. £800-£1000 done cheaply. £2500-£5000 done exceptionally well inc parts removal, full shutline/ inner panels.