Hi Neil,

This will most likely be due to the recovery option you have selected when you reconfigured log shipping. You need your log shipping setup in Standby mode which will leave the secondary database online, but read only.

So maybe you want to re-initialise log shipping again, but this time choose the Standby mode.

There is a better explanation here:

http://www.microsoft.com/technet/prodtechnol/sql/2000/maintain/logship1.mspx

Hope That Helps - Nathan