BRP and ukba reference number?

[auz]

I am filling application have 2 small doubts

a- It asks do I have BRP ? What is BRP Number? What is current status if I do not have?

I had BRP when I had student visa. While applying for PSW i sent it. They destroyed it and gave me PSW inside passport. Now I am applying for tier 2, so a bit confused what i have done is

selected yes that i did have BRP
Mentioned the BRP Number
In status of BRP I selected expired and returned to UKBA?

Is this correct?

b- It asks do you have HOME office Reference number?

I understand that when home office communicates with us, they give us refernece number, for example when you get psw you get one which is in letter, for biometric you get one.

I do not store these letters, so I do not remember it.

Can I select NO or is it Yes?

I have found an old lettter which is of the time when home office recieved my application for PSW.

I have selected Yes in the option that I do have home office reference number and selected yes(Though this is not the last reference number, do i have to enter the last one) or can i select the no?

My whole form is complete except these two doubts if some people can let me know it would be a great help.

Much thanks in advance