When did you first enter the UK?

When did you first enter the UK?
This is the date you entered the UK when the period of stay you are basing this application on started.

HI,
I am currently on tier 2 general Visa and had completed my 5 years. As I was filling the Visas and Immigration form, I have encountered a problem with the question The date you first entered the UK?
On my current visa, I have entered the UK in March 2015 but I have also lived in the UK from 2003 to 2008 on a residence permit visa(LTR). Can you please advise me if I should enter the date when did I first enter the UK as in when I first enter with my current visa or the date 2003 when I first entered the UK.

Thank you for your time and consideration.

Date you entered in tier 2 as you're ILR is based in tier 2 and not a previous residence a long time ago.