Cross country. Unsurprising with our MPs.
To commence the CPL(A) training, you have fulfilled the cross country requirement by getting your PPL.
When applying for your CPL(A) (ie you have finished all the other application requirements) you must have completed a 300 nm cross country flight as per LAS D1.2(D).a(ii).
The definition of cross country time, I believe, is time where you are >6 nm from the Airfield Reference Point (ARP). You must check this one with the CAA, however.
The above applies to the modular route. Integrated might be different - different planet!