LED Recessed Brick Lights with Interchangeable Bezels

I’m looking to put this into my 150mm step up to my patio along the front are they bright enough to light up the lawn in front do you think
That is all subjective, if you use a fixture that is too bright it will cause glare to anyone walking back towards the patio from the garden. This will more than likely work well for your needs. If you are using more than one along the edge of the patio we would suggest that you temporarily put a lead and plug on the fixture and work out the spacing that is right for you.

What IP rating does a light need to go 1.5m away from a pool
The IP rating is not the main issue. Within two metres of a pool the lights need to be SELV (under 24 volts). This means LED light with a remote power supply (housed somewhere outside of zone B) is the best solution. We would suggest something like this.

Can this light go in a wall that is 1m away from a pool
No, this fixture does not have a sufficiently high IP rating for your proposed location

Is the led bulb replaceable?
This is a built in, non replaceable LED. The lamp life is around 30,000 hours.

Is there a recommended height above a step to install a brick light to get the best lighting?
The height at which to install the fittings is all based on personal preference. If you are intending to use these as a guide light then I would suggest no higher than 500mm.

Are the dimension stated that of the overall size of the steel face or are they the size of the part that goes in the wall? If the overall size is the fascia what are the dimensions of the part that fits in the wall? Can you also confirm they will fit in the opening left by the removal of one brick from the wall? I don`t want to order 5 and have to return because they don`t fit into a single brick opening.
The size of the fitting (the fascia) is width 240mm x height 100mm and projection 85mm. The cut out measurement is 230mm x 85mm (this is the void needed for the fitting). With these measurements you can work out if the light will fit into the space left by a brick (you have not stated brick size and if it is standard size). If you require anything further please contact the sales office on 01780 767617.

I have black brick lights at the moment that have disintegrated and all of the housing and fascia is crumbling. Are these type guaranteed not to do the same or rust?
At a little over £20 including VAT these fittings do represent good value for money. The housing is made from cast aluminium so will not rust. Aluminium can oxidize if exposed to air. So if the housing is scraped or scratched during installation touch-up up the point to avoid oxidisation. The fascia plate is stainless steel - wiping this occasionally with machine oil will maintain the lustre.