Speak to your RO (I assume your VP) and be frank about our aspirations to be on the leadership track.

Not all HOD wants to go further and SLs may not ask you/assume you are happy being HOD. Luck plays a role as well, especially if you are out-shadowed by high performing colleagues, as SLs and Supt's attention will likely be on recommending that person first.

Also, be prepared to take on at least 2 different portfolios so you can say that you have a more macro perspective of matters, not just confined to your portfolio.

I would consider asking what are your areas of growth, as well as what additional exposure he/she thinks you will be good for, and try to manage work or projects beyond your current portfolio.

That would help speed things up a bit. At the end of the day, CEP matters more than performance grade when it comes to advancement beyond.

There is also a specific archtype they look for when they want to recommend for leadership roles beyond HOD.