'clamber over' is correct and usable in written English.
It means to climb over something, usually with difficulty. For example: I had to clamber over the large rock blocking my path.
Just as Nicole was about to clamber over, she noticed that Frank was hanging back.
His daughter has one of his Plastic Orgone Chairs to clamber over in her room; the kitchen table is his, as are the Diode lamps scattered throughout.
He has made a thing to clamber over and explore, a much-enlarged version of the playfulness of the children's park.
People clamber over one another to grab the best seats, swigging beer and drawing on cigarettes as the lights go down.
Will Mr. Sharon always find another hoop for the Palestinians to jump through and a higher bar for them to clamber over?
Groups of people in bright bathing suits clamber over reddish rocks brandishing spades hired from a nearby surf shop for £2.50 an hour.
Crabs clamber over the ice.
They just clamber over any obstacle.
Farther down the gorge, two fishermen clamber over boulders.
The fourth hurdle is more difficult to clamber over.
Clamber over the sofa, swing from the door frame and balance on the skirting board.
