Hi Ed, a couple of questions:
- what type of hollows - Standard brick or large grey block?
- How wide is the gate? The wider the gat, the more force that will be pulling on the top of the post
- Chemset is good but use the chemset bolts.
The bolts are "set" in place ready to slide your attachment over and fix to the bolt with a washer/nut ie: not anka screws as they are for dry fit, not designed for that purpose, may not achieve the same strength result as a chemset bolt Also from memory, there is tubular "flywire" that is pushed into the cavity and the chemset bolt them pushed into this. Cant remember the specific use case (possibly for large cavities in something like grey block to minimise the amount of chemset required) but do some research.
- Careful how much weight is pulling on the bricks as generally the brick wall is a "veneer" meaning they are not structural or designed for forces pulling or pushing the brick in/out. The dolly will obviously assist in removing this issue if set up correctly. If in doubt, post concreted in the ground 800mm min.