Is it worth using a sealant on a newly laid monoblock driveway

yes, it helps to preserve the colour etc. especially on concrete paviors and as early as possible. I prefer Matt or satin finish. Wickes own brand is good.

if they are concrete you need to get rid of the efflorescent first...feels soapy when wet. it is the oil used in manufacture to stop the concrete block sticking to the mould.