The 2.4m and 3m versions come with two posts, one at each end. The 3.6m, 4.2m and 4.8m versions come with three, with the extra post carrying the middle of the run. That is why the longer lengths stay rigid rather than flexing in a strong wind. Allow for the middle post when you plan the line, since it will land roughly halfway along.

Yes, and it is one of the main ways people use it. Bare, the pergola frames a view and adds height. With trellis fixed between the posts it becomes a proper divider, screening one part of the garden from another while still letting light and air through. Trellis also gives climbing plants a closer grid to grip than the posts and top rails alone provide.

Dividing space and adding height. It separates beds from a patio, a water feature from a lawn, or decking from the rest of the plot, marking the change without walling it off. It also works as a standalone feature to train climbers along, and as a way of giving a long flat garden something to break it up partway down its length.

Bolt down feet are for paving, decking or a concrete pad, where you want the posts fixed without lifting the surface. Spike feet drive straight into a lawn or a border and are the fastest option on soft ground. No feet is the choice if you are setting the posts into concrete, which is the most solid of the three and worth it on an exposed boundary.

It does. The pressure treatment inside the timber is what protects against rot and fungal attack, and that does its work whatever the surface looks like. The Light Green stain on the outside is the part that fades in sunlight. Re-coat every two or three years, more often on whichever face takes the afternoon sun, and the colour stays consistent along the whole run.