Liam

Thank you for your response. I agree if you use the descend now function then the behaviour is as you describe and as expected.

However the manual states that for descents starting more the 50Nm before the Top of Descent point should be initiated using the cruise descent. I looked this up in the manual and its says

CRUISE DESCENT
Cruise descents can be started in the cruise phase when the airplane is more than 50 miles from the T/D point.
A cruise descent can be started by selecting a lower altitude on the MCP,
entering the new altitude in the CRZ ALT line and executing. A VNAV cruise descent is commanded at the current cruise speed and approximately 1250 feet per minute rate of descent.

The autothrottles adjust thrust to maintain the target descent rate; pitch maintains the commanded speed. Thrust levers can be manually positioned to adjust the descent rate.

When I follow these instructions that is when the aircraft pitches down to 3000fpm until it captures the new cruise altitude. Its not what is described and I thought I maybe setting things up incorrectly.

Thanks

Chris