How complete was her mindwipe??

Today I'm watching 'Partners in Crime', the first Donna episode since her Christmas Special a couple of years before hand.
Early on, after a bit of detecting, Donna goes up the hill to talk with her Grandfater Wilf, (or to get away from her Mother, really) and asks Wilf if he has seen anybody floating around in a Blue Police Box.
http://www.chakoteya.net/DoctorWho/30-1.htm
Partners in Crime
Original Airdate: 5 Apr, 2008
Quote
[Allotment]
(Granddad is the newspaper seller from Voyage of the Damned, and he has got a nice set-up in his allotment shed. There is also a small telescope and a camp stool nearby. Donna walks up with a thermos.)
WILF: Aye, aye. Here comes trouble.
DONNA: Permission to board ship, sir?
WILF: Permission granted. Was she nagging you?
DONNA: Big time. Brought you a thermos.
WILF: Oh, ta.
DONNA: You seen anything?
WILF: Yeah, I've got Venus, there with an apparent magnitude of minus three point five. At least, that's what it says in my little book.
(Donna puts a tarpaulin on the ground next to him.)
WILF: Here, come and see. Come on. Here you go. Right?
(Donna looks at the bright evening star.)
WILF: That's the only planet in the Solar System named after a woman.
DONNA: Good for her. How far away is that?
WILF: Oh, it's about twenty six million miles. But we'll get there, one day. In a hundred years time we'll be striding out amongst the stars. Jiggling about with all them aliens. Just you wait.
DONNA: You really believe in all that stuff, don't you?
WILF: It's all over the place these days. If I wait here long enough.
DONNA: I don't suppose you've seen a little blue box?
WILF: Is that slang for something?
*DONNA: No, I mean it. If you ever see a little blue box flying up there in the sky, you shout for me, Gramps. Oh, you just shout.*
WILF: Do you know, I don't understand half the things you say these days.
DONNA: Nor me.
WILF: No, fair dos. You've had a funny old time of it lately. There was poor old what's his name, Lance, bless him, and that barmy old Christmas. I wish you'd tell us what really happened.
DONNA: I know. It's just, the things I've seen, sometimes I think I'm going mad. I mean, even tonight I was in a. Doesn't matter.
WILF: Well, you're not yourself, I'll give you that. You just, you seem to be drifting, sweetheart.
DONNA: I'm not drifting. I'm waiting.
WILF: What for?
DONNA: The right man.
WILF: Same old story. A man!
DONNA: No, I don't mean like that. But, he's real. I've seen him. I've met him, just once, and then I let him fly away.
WILF: Well, there you are. Go and find him.
DONNA: I've tried. He's nowhere.
WILF: Oi, not like you to give up. Do you know, I remember when you were about six years old, your mother said no holiday this year. So off you toddled, all on your own and you got on a bus to Strathclyde. Ha! We had the police after you and everything. Ha, where's she gone, then. Where's that girl, hey?
DONNA: You're right. Because he's still out there, somewhere. And I'll find him, Gramps. Even if I have to wait a hundred years, I'll find him.
End qUOTE
Didn't we find out, way back when, that IF Donna encountered The Doctor again, it would fry her mind?? What happened??
--
Daniel