Ford KA over heating

Hi,

So I picked a new car up last night, Ford Ka 55, 1.3 36,000 miles. However on the way home the heating light came on, which did concern me, but it then went off a few minutes later. I then came on again for even less time and went off again before I got home; trip was about 30 miles. The bonnet felt hot when I got home, so I checked the engine coolant level and it was far below the minimum. Topped it up with some water and went for a 5 minute drive, bonnet did feel a tiny bit warm in one spot after.

Should this be okay to drive? my dad says I should wait a few days for a booking at the garage and not drive it, but i’ve aranged to go see a friend about 60 miles away in 2 days. I think, given the coolant fluid was so low, and it went off while still driving it shouldbe okay. Should I just take it for a slow drive to see what happens, and hopefully it will be fine? Is this a bad idea? Are KA’s known for these problems?
I bought it privately, so I can’t really take it back and ask them to sort it out.

Thanks for any replies, i’m a total novice with cars; this is my first one!