I'm looking for an agent that can help with finding office/retail/warehouse rental space in Phuket. Is there anyone that specialises in this? Most real estate companies seem to be residential focused or commercial sales.

Or is the only option to drive around looking for myself?

Most people looking for this type of setup usually find a conveniently located shop house, and go from there. There isn't much money in handling rental spaces like you're looking for, hence not many companies offering what you're looking for.

I would be looking for something a bit different from a shop house, larger with higher ceilings. Getting several shop houses could be a possibility but it would seem like a lot of wasted space as I wouldn't need the 'house' part on the upper levels. It seems like there are many businesses that do rent shop houses and just do not use the upper levels. Either that or they are used without any windows as the front is covered completely by the shop sign. Is this correct?

Any ideas on how to find a 'warehouse' type space? Something similar to the larger tyre shops but without the fully open frontage.

Rent some land, build your own shed/warehouse

End up cheaper if it's a long term thing.