Yes, it is normal. If the suite isn't being imported it's being built to order in the UK and with that comes delays in delivery of components; backlogs in work and being bumped down the priority list because they've had a bigger and better order with a determined delivery date.
Same problems if it is being imported with the added complication of getting it into the country. These companies often wait until they have a container load or can buy a space in a container at the right price before transporting it.