Stolen pension

How much money did the pensioner have before being robbed?

Problem



A thief stole $\frac6{11}$ of a pensioner's money and spent $\frac6{11}$ of the money stolen. The thief was then caught, and the remaining money was returned to the pensioner.

The remaining money was £425 less than the amount the pensioner had after being robbed. How many pounds did the pensioner have before the theft?

This problem is adapted from the World Mathematics Championships