Well, I did A level Spanish and did OK got a B grade, but ..?

Don't worry - A level does not make you fluent. It's not intended to, it's just a step on the way there. A level takes you to approximately B2 in the Common European Framework of Reference for languages - degree is C1/C2. Compared to degree level it's quite low and it's unlikely you'd manage to follow films or TV progs without subtitles. You are entirely normal!! You can either continue with Spanish at uni, or you can work on your own to improve your Spanish - what worked for me in several languages was, having both an audio book and the printed book so that when the audio book is too fast [ they are always too fast] you have the printed book open in front of you. I suggest audiobook or radio, as then your ears do all the work, without the distraction of pics. It's as basic as that - the more you listen, the more your ears get attuned to what you're hearing - try Spanish radio online too, find it through google.es, find books and CDs on amazon.es

I never studied a language for A levels. But I lived in Spain for 3 years.

In my second year, I met up with (and ended up dating) a girl who studied Spanish and French in university. She had done GCSEs, A levels and a university degree and from my two years in Spain, I had gathered more of a solid foundation of the language than she had managed. I learnt through speaking with friends in Spanish and being forced to use it for at least 80% of my waking life from day to day. She had studied for hours but relied on English to live. I think that made all the difference.

I wouldn't be discouraged, I think it's quite normal for A level students to lack in fluency. If you're really serious about learning the language to a decent level I'd suggest going to a Spanish speaking country. Even a few months over the Summer would change your B into an A. Within a year or two you'll be practically fluent with the ability to watch films and converse with people about a vast array of topics. I was able to achieve that within two years without any sort of a base to begin from.

These are obviously just my personal experiences, people are all different and what works for some won't work for others.

If you want to understand the a lot more informal, colloquial, widespread, every day variety of spoken Spanish then you need to select this course https://tr.im/d6zMe the online Spanish program from Rocket Languages

With the Rocket Language program you will find out and emphasizes modern, daily, spoken Spanish, you will learn to speak Spanish just like a native speaker does in his typical daily live.

This program contain the far more formal and correct Spanish that you would need to have to know, that you would be expected to know so if is what you are you hunting then you came at the right spot.

I had good A levels in French and History and was awaiting my results in Spanish when I was offered a place at a Russell Group institution, subject only to my passing. I did so at the absolute minimum level and heard afterwards that they would never have given me a place had they suspected that I might do quite so badly. But I worked hard, my first year included six months at Salamanca University and I ended up with an upper second, that, but for my overconfidence in one paper would have been a first. I found I like my subsidiary subject, Portuguese, more than my Spanish major and went on to do a PhD in Brazilian studies. My disseration was published and is now in its fourth edition in Brazil and still selling (50 years later).

Don't dispair: my Spanish was far worse than yours when I sneaked through my A levels, I largely learned to understand spoken Spanish by teaching English to Spaniards (to eke out my income) while a student at Salamanca.

Well Spanish although and easy language on paper I find on tv is hard to understand because the people speak so fast and they pronounce things so differently than an english speak might, its hard to recognise the word. A level spanish isn't actually that complex i'm afraid and a lot of it is general stuff, and maybe not the stuff that is said on tv. You have to just keep watching, turn subtitles off so you have to use knowledge, nothing comes easily when you're using a non-native language, your ears must adjust! Try putting spanish subs so then you can recognize the words more easily and how they are said.