Flora, is the weather the same all across UK ?. Yes, seysonn - the climate is pretty much the same all across the UK with far less variation than in the US. Remember, many of the States are larger than our entire country. Essentially the majority of the country can be treated as one zone. In fact we don't even use a zone concept here since everywhere is roughly the same. It is quite possible UK posters have no idea what the zone box is for and wouldn't know their zone anyway. I had to look mine up but although it says 8/9 that really only fits for the minimum temperatures and gives no comparison with a US 8/9. There is nowhere here where it is reliably hot enough to grow large healthy outdoor basil plants without some sort of protection. Outdoor plants are usually runty and often ill looking. Some years it will do OK but it is a gamble. This year we have had (and when I say we I mean the entire country), the coldest least sunny spring and early summer for 50 years. We also have pretty much universally reasonably good soils so nutrient problems are not a common issue, especially for Mediterranean herbs like basil. Although, the OP's zone is not at the head of the post he/she said they bought the plants at Homebase, which is a UK store, and fed them with Baby BIo, a UK product, so I then checked their location and it said UK. Also I can usually tell by the language whether a poster is US or UK based, although sometimes the Canadians confuse me a little ;-) Bottom line is - basil, like tomatoes, is not suited to outdoor culture in the UK. It can be done but it is a project and is often a failure. Plus the OP did not separate the multiple plants. No amount of tinkering with feeding will overcome this. They need to be separated and protected. This is my basil - indoors in a container.

Dutchman's pipe vine AKA Aristolochia is a whole genus of hundreds of plants that grow from zone 4 (NE US) into the tropics. Without information about which kind you have, this question is difficult to answer. Where are you? Can you take clear close-ups of the flowers and leaves and a photo of the plant overall and post on the Name that Plant forum to get IDed? Do pollenators visit the flowers? Have you tried hand pollenating with a paintbrush, moving pollen from one flower to another?

I would bet underwatering, too. In New York in the heart of summer, I end up watering pretty much every day, especially my plants that are in containers rather than a raised bed. Did you mix a lot of compost in the soil when you planted, too? That seemed to help.

A few hours of LED light each day is clearly not enough replacement for plants (like echeverias) that crave full to shaded sunlight. Mine winter with grow lights up to 8-10 hours a day on a timer, even that is not enough to replace what natural sunlight provides. I set them about 2-3 inches from the actual light bulb, so if you can, adjust your lamp closer to the plants. If you are worried about overwatering, get a small fan to ventilate, and make sure the water doesn't sit in the bottom. Plants wise, your plants are looking fine. As crenda mentioned, flowers wilt and dry away. The most important things to keep watch are how the leaves grow. Healthy roots and leaves = healthy plants.