Hi methodmza_uk
The grassy plant that is mentioned is Mondo Grass I'm afraid -
Ophiopogon japonicus and will last a month or two if you're lucky, it will slowly get covered in algae because it isn't growing and then die.
It may be a source of comfort to know that I bought some when I started out in this hobby. In fact pretty much all of the plants I bought were non-aquatic from my first trip the garden centre. Looking back it was a good thing, it made me learn more about real aquarium plants and how to grow them.
Some shops will always sell non-aquatic (or semi-aquatic) because people like you and I will buy them. They are attractive, until you know what they really are. There is no label on them saying "I am not a real plant and will start to die as soon as I am put in your fish tank" - which is a pity because the general public have no idea. So the plants die and we will either buy more, give up on them, or learn about why they are dying and buy some real ones. Then the real ones may die, or we get algae, so we either give up entirely or learn more about how to grow real plants. If you choose the "real plants" path and want to grow them well the learning process really takes off and if you like it you may get hooked - like me and lots of other members. Take a look at the planted forum if you're interested.
People have different goals. Some don't want to grow plants, but they like pretty natural looking decorations that will last them a few weeks (like Mondo Grass), then they are prepared to bin them and start over. It may cost less short term because they don't have to think about lighting and the other elements that are essential for plant growth.
Realise what your intended goals are, and then seek the knowledge that you require to acheive them. From the thread title and your current layout it seems to me that you like plants. This is good.
Nice tank, lots of potential.
BTW Sunflower/olive oil works better than Vaseline. A credit card is great to smooth out the air bubbles.