Her

[dave1948]

5d Rare cute eccentric bird (8)
?E?A?U?E
Looks like an anagram but I can't work it out

12d David's sometime HQ is with a dynasty from the east invading put out of action (7)
M?H?N?I?

[penelope2]

How about 'Creature' for 5d.

[boxtops]

5d creature

[Baldric]

Anag rare+cute

[Mamyalynne]

Mahanaim

[Mamyalynne]

http://en.wikipedia.org/wiki/Mahanaim

[Baldric]

12d say (7) show 8 ??

[factor-fiction]

You are showing 8 letters not 7 for 12d

[factor-fiction]

Okay, Mamya has it

[Mamyalynne]

ah my answer may be wrong then

[factor-fiction]

The MAIM bit looks okay, Mamya.
I can't work out the rest yet

[scorpiojo]

Han dynasty

[Mamyalynne]

Oh I know it fits the clue, but does it fit the letter count?

[dave1948]

Thank you all 9 answers in seconds.

Creature is 5a as I have seen the error of my ways

Mahanaim I have never come across

[Mamyalynne]

You are welcome Dave.

[dave1948]

Thank you all. Especially Mamyalynne who can still get it right when I put duff information !

[Mamyalynne]

That's one way of looking at it - either that or I cannot count, glad to have helped and learnt something new in the process. :-)