Compost around new decking area

My husband is building a decking area to cover all the builders rubble. All the rubble will be enclosed and there will be deep planting areas around it. These will require large amounts of top soil and compost some of which will be bought and some will come from the pond when it is dug, which won't be too long. He promised!

My question is would it be a good idea to shred the plant material, avoiding live roots and seeds, and use that as a base layer for the soil I import? (I still have the remains of my old compost heap in the corner which I stoped using because something or other bit me resulting in a massive infection and the antibiotics etc). It has to be cleared so it'll be gloves and a long handled rake. If I get the photos up you will see brambles now growing in aforesaid compost heap so obviously those will be dug up. I have been told shredded brmables make good compost.

If I can't use it around the deck I will have to take it to be recycled as garden waste and by more soil myself which seems an awful faf and expensive.

 

All I would add is that really the shredded stuff should be rotted down first, I'd go for the old compost heap first.
Bearing in mind organic matter has a habit of slowly disappearing, so whatever you use, if you add a lot, the bed will sink.
Top soil is best in my view, and be careful to only use the top ft or so from the pond diggings, the rest will be subsoil if it is anything like round here.