Mabel
I'm not in J9, but in the same boat as you - completion set for 2 weeks, but NO habitation licence as yet.
Best advice to you is to start hassling your Solicitor
AND Polaris World direct on it NOW.. PW will be able to confirm if the certificate is there for your own property as of now. If it isn't, get your solicitor to get in touch with PW and make it clear that you WONT complete without it (even if you are prepared to).. Because PW won't be getting their 60% on the date they expected it, it will give them a incentive to push it through in time.
I started hassling last week, and am continuing to do so. We haven't actually got the cert yet, but my Solictor was told today (by PW) that it will be ready tomorrow, whilst I rang PW myself and they said it would be
Next Friday. Of course, I won't believe either of those until it finally happens, but it's suddenly sounding a lot more promising.
Hope that helps, and good luck