Bosch WFF1401 - slowly fills with water and has a small leak?

I have a Bosch WFF1401.
We recently moved house.

I now find yesterday and today that even when there is no wash on, water is slowly filling the tub.

There is also a small pool of water underneath the machine.

Note - the following are completely dry:
1. Hot inlet fitting
2. Colt inlet fitting
3. Outlet waste pipe

The questions are really -
What could be the cause? Can I fix it?
Is it worth just investing in a new machine (15 years worth of use with no problems up to now)?

Many thanks

Tim
March 2015