moving setts

[griff]

there is a large number of setts on my recent installation able to be moved / rocked by hand. they also 'clink' together when a laden wheel barrow goes over them.
i am told by the contractor, this is acceptable, as it
"is a flexible mat over the sand and sub base"
do you agree, how much movement should be acceptable for setts
thanks
griff

[84-1093879891]

Are these definitely "setts", ie, blocks of dressed stone? Or are you talking about concrete/clay paving blocks?

What's the width of the joints?