I am going to start a planted tank soon, and since it's my first attempt I'd like anyone that knows roughly what they are talking about to have a look at the list of equipment below and tell me if I am heading in the right direction or if anything needs updating/changing.

Aqua One Regency 80 tank (180l 80W x 40D x 70H cm) I know it's a weird shape tank but it was free
Eheim professional 3 250 2071 canister filter
Dennerle Eco Line Thermo Tronic 40W undergravel heating
Dennerle Disposable 300 Quantum CO2
4x Hagen Life Glo T5 HO 24w
tank hood covered with Mylar instead of standard reflectors, I don't know if it's better but it was fitted by the previous owner
JBL aquarium thermometer
Eheim air pump 400
newave 1000 powerhead
Vecton UV8 steriliser with T5 8W uv light

I have not decided yet but I will probably go for the Topica Plant substrate (1 bag of 5KG should be enough? or could I use 2 and have a deeper substrate?) I have not decided on the gravel yet but something quite light in colour I suppose since it's such a deep tank...

What do you guys think? any advice?

thank you

Is this a shopping list or stuff you have in hand?

Don't use the under substrate heating. Expensive and easy to make a mess when pulling up plants and such. The theory behind it hasn't proven to work out in a planted tank. I don't think it is capable of keeping a tank warm enough on its own either, get an inline heater or a submersible one.

Regular pressurized CO2 is cheaper in the long run than the disposable stuff.

Usually it is better to have lighting that spans the length of the tank and 4 T5Ho bulbs are a lot more lighting than needed. If you can turn off 1,2 or 3 as you please it will make things easier in the long run. If you already have this fixture if you can suspend it above the tank that would help with the dark corners on either end of the tank.

Some people like to run air in the tank at night when the CO2 is off. Air pumps are noisy and just making sure there is a good ripple on the water surface with the circulation or spray bar from the canister filter provides plenty of gas exchange so I wouldn't want to use an air pump if I didn't have to.

Tropica suggests an inch of the substrate and for your tank suggests 4 bags plus gravel on top. It seems to be a mixture of clay and sphagnum moss, perhaps you could research further to find a naturally hard or fired clay product that can do the same job for less. I found a product used for potting pond plants that was very inexpensive.

I don't know if you have found it yet, the UKAPS forum is really good too. http://www.ukaps.org/