I have also considered combining economics and marketing but I'm not too sure if that's even an option I can pursue due to location.It would then be significantly easier if you specify what the location you want to look into. I don't know why you want to restrict your options by restricting your location, but if you want to restrict your location, it's probably the first thing you should specify if you are looking for advice.
A quick google search shows that there are only a handful of universities that do a joint undergrad in marketing and economics:
You might have a problem applying to the Scottish universities with an Access course, but you are fine with Goldsmith and Liverpool Hope.
I know it might seem like an odd mix but there jobs which require marketers to have computer science knowledge or even a bsc and msc in both. There are some business related jobs which require a computer science degree but a business background.This is the first time that I have come across someone saying you need a degree in order to get into marketing or computer science. As far as I know, you don't need anything to get into either fields in industry.
Unless you intend to pursue a PhD that involves both computing and marketing, then I don't see the rationale in doing both subjects.
My dream would be to gain experience in both sectors while starting a small business, I feel like both degrees would help in learning how to marketing ,brand and management the business, creating an app, website and whatever else tech has to offer.
Keeping things simple huh?
The problem wit starting a business alongside of a job is that the employer might not like it. If it's in a similar industry, the employer will raise issues of it being a conflict of interest. Most employers wouldn't care if you're in a junior role, and it's something small and doesn't affect your work. If you intend to start a business, what would it be in exactly?
If you intend to start a business in tech or marketing, then you don't specifically need degrees for them. The only time where I would see the possibility of having a degree in this context would be something in computer engineering, but that's if you intend to go into the manufacturing side of things.
If you want to do a course to learn to create apps and websites, you can do courses that aren't degrees.
I don't know which area in tech you are interested in since it's not exactly a small niche e.g. cybersecurity, AI, data, networking, web development, project management, business analysis, etc.
I realise work experience might be an issue if I decide to do a computer science masters but Kent offers a placement year and modules in AI which is a bonus.
Most computer science master's degrees don't ask for work experience. They usually mandate that you have the right grade in your undergrad. Some degrees will ask for a quantiative undergrad with quite a bit of programming, but that's for advanced computer science courses.
Some universities might consider relevant work experience up to 3 years to be equivalent of an undergrad in computer science, but that's in place of a degree with programming, if the course requires it.
computer science degrees requires an access in computer science or physics /maths which none of my local colleges offer. Have you called up the undergrad admissions personnel in the computer science departments of the universities that you want to apply for? If you did and you have explained your situation to them, you would have realised that you could supplement your Access course with an A Level in Maths. This would allow you to meet the necessary entry requirements.
I suggest you double check before you go off at a tangent.