I used a rather unsafe way of compressing the springs.
I first compressed the spring and then tied the middle coils together with thick synthetic rope on opposite sides and mounted the springs on the shocks.
After securing the coil on the shock, I cut through the rope with a sharp stanley knife.
I do not recommend you follow my idea as it was b***dy dangerous!
i think if you search on-line for 'Motorcycle spring compressors' you'll find something more suitable and safe.
Or just grab Robin's offer of borrowing his.........
...peter