Whilst looking through the Cisco Learning Network I came across a rather interesting post, which raised an issue I was not totally aware of. Turns out that you have 3 years from the date of passing your first exam to complete the CCNP track.
The actual criteria is that exams are valid for 3 years from the date of completion, so if I get into gear properly I have until the beginning of 2010 to complete both my CCNP and CCDP!
Thought this might be a useful fact for other people following a similar path.