We would rather tell you this than have you assume it, so here it is roughly as it works.
Same day and next day
Possible more often than you would think, particularly on local work where something has fallen out of the diary. If it is straightforward, in the North West, and does not need notification, ring and ask. The worst answer is no.
A few days
The normal booking. Enough time to look at the access, pick the right vehicle, write the RAMS and give you a lift plan you can put in front of a site manager.
A week or more
Anything that needs a specific vehicle rather than any vehicle. The 858 rigids and the extendable trailers are in demand and there are not many of them. If your job needs full reach or full deck length, a week is realistic and two is comfortable.
Three weeks and up
Notifiable loads. Not because of us — because the notice period is a legal minimum that cannot be shortened by anybody. See the piece on notice periods. Also anything requiring a road closure, since traffic management is booked through the highway authority and has its own queue.
The seasons
Late spring and early summer are the busiest weeks of our year, because that is when the school modular jobs, the festival builds and the stadium close-season works all happen at once. If your job is in that window and it moves at all, moving it a fortnight either way makes it easier for everybody.
December is quieter for lifting and busier for storage. January is quiet full stop.
What we will not do
Take a booking we do not think we can honour. If the diary is tight we will say so and give you a date we can stand behind, rather than a date you would prefer to hear.