From UK salary website, for what it's worth.
■Average starting salary for graduate software engineer: £27,000 (salary data collected Nov 09). Salaries vary depending on the size of the company and the location.
■Typical range of earnings for software engineers after around three to four years: £35,500 - £38,500 (salary data collected Nov 09).
■Range of typical salaries for a senior software engineer (e.g. after 10-15 years in the role): £47,000 - £49,500 (salary data collected Nov 09). Salaries can increase further with bonus schemes and incentives.
■Salary is dependent upon the company, location and nature of the employer's business. The highest salaries can be found in the finance, pensions and telecoms sectors in London and the South East.
Maybe you should have a talk with your boss about a raise.