Cryptic Quiz - Dogs

[Shegs]

All these answers have something to do with dogs.
I’m stuck on these last few :
1. Endlessly honest swaps first for second class source and destination of Calcium. (5)
2. Wet kilometre sound minus 100. (4)
3. 2D Fred and sweet Bertie have short legs. (6)
4. German is following stupid quadruped ace with point to help. (10)
5. Buck swaps 1st December for 3rd completing owner’s circle. (6)
6. Following under cover of bottom. (5)
7. Anagram with 500 and 550 and two points but without Royal Mail close to both sides of exit. (4,6)
8. Good word Bab’s lad has no naughty canine round about. (2,4,5,2,1,3,3,4,1,3,5)

That last one is a real stinker!

Many thanks
Shegs

[Shegs]

Just numbers 6 and 7 left to solve.

[cashier]

6 very iffy Frump
WordNet gives as an example, 'she's a real dog' and also dog as a synonym of frump.

[mallyh]

6 tails?

[Shegs]

I think tails is probably better than frump, but I did wonder about track or trail.

[cashier]

I think tails is a lot better than frump, and so obvious when you see it.

[aelmpvw]

7 could be land rover but i can't fully parse

[Shegs]

I thought of Land Rover too Aelmpvw but couldn’t work out why.