Tier 5/Working holiday time in 5 year qualifying period

I have a question regarding when I would be eligible to submit an application for citizenship. I am aware that I must spend 5 years + 1 year without time restrictions, but find an application date difficult to determine based on the application form 2.1 wording: Enter the day you first arrived with a view to staying in the UK on a long-term basis. The relevant dates are below:

15/04/2006 - Arrival on Tier 5/Working holiday
07/03/2007 - HSMP Approval sticker (in-country switch)
10/04/2007 - First re-entry after UK absence with HSMP approval
14/02/2012 - ILR granted same-day, 28 days before 5 year qualifying period.

I will have spent 5 + 1 years (Tier 5 + HSMP + ILR) on 14/02/2013 but some of that time would have been Tier 5/Working Holiday - would it be true that I should not have arrived with a view to staying long term on that visa and cannot enter that as the date?

If that is so, my HSMP was approved in-country, so do I have to list for 2.1 the first re-entry date (10/04/07) or the date of HSMP approval as I did for ILR (07/03/07)?

Thanks in advance

put 15/4/2006 in the form. The answer to that question has nothing to do with the 5 years qualifying period. You don't need to worry on getting it wrong. It will not affect the application.