Dependent - "Long Term Staff Partner, upto 3 yrs?" -HELP

[acchan113]

Hi

My partner has had a Tier 2 (ICT) Long term staff visa granted for 2 years (03/09/12 - 02/10/14).

She has had her Tier 2 (ICT) long term staff visa extended an extra 3 years (03/10/14 - 02/10/17)

I now want to now apply as a dependent of my partner, we meet the maintenance requirements.

Do I apply for "Long Term Staff Partner, upto 3 years" OR "Long Term Staff Partner, upto 5 years"?

I rang the premium service helpline for UK Borders and they have difficultly understanding. I only want a "Tier 2 (ICT) staff partner visa upto 3 yrs as we plan to move back home together (01/01/2017) but am unsure if I need to apply for "Long Term Staff Partner, upto 5 years" as she has a visa totallying 5years that 2years have been used already.