moving in to investment property

I have been living in rented accommodation for a few years while letting out my house to individual tenants. I am now going overseas for 4 months so I have decided to let my rented property go as I can't really afford to keep it on while I'm away.

My question is: can I take a room (which is vacant) in my investment property while two other tenants are in situ? The house is a 3 bedroom house and one tenant left 2 weeks ago. It would really suit me right now to take this room for my things and also to live there temporarily when I come back until I'm sorted. If so, do I need to give them a few months notice of my intention?

I would really appreciate some advice on this.

I don't think it would be as simple as just giving them notice and then moving in.
You would be completely changing the nature of their tenancy.

They are currently tenants, with full rights and protections under law.
If they were living with the landlord, they would become licencees, with no rights, and no security of tenure.

Threshold might be able to give you some advice on this
http://www.threshold.ie/advice/help/

Ok, I'll check that out. Thanks Berni