Hi Harmony,
I was a FT researcher for nearly 4 years between MSc and start of PhD. Therefore, when I was at the end of my first year, I was in the right place, right time , to take a Pt research job at a different Uni on an unconnected project. I work 5.5 hours per week. I am still doing this project - been ongoing for 6 months now and it is heating up, so to speak so I'm working a bit more than the contracted hours. I find it an excellent means of additional income - it is much more lucrative than a bar job for example. I am in a discipline at Uni where I have not experience of the subject so I'm unlikely to get demonstrating jobs (hasn't happened yet - 1.5 years into PhD) and I have contact with patients which will look very good on my CV. It is sometimes difficult to juggle - but it just means being more organised. I think you should take it as the supervisor wouldn't have offered you it if they didn't think you could do it. Perhaps it'll be easier for you that it'll link into your PhD. However, make sure you and your supervisor decides on what is research job and what is PhD research or you may find you've bitten of more than you can chew. Communication is key to balancing these demands. Good luck