At this mileage they are due for replacement as you will notice a much smoother ride with new units. However, i would get a second quote as 30k is OTT.
The shocks do not appear to be leaking. The rubber dust boots are ripped bit this is not a really a problem. 30k is way over the top as they have quoted to replace every item on the shock, and 5k for back brakes is also OTT.
What car is it?
I had one a while back. I could touch the back window from the driver's seat.
I sold it in the end as it was too small and i was worried that it would not fare well in an accident.