Should I lie in my job interview?

Just don’t tell them then give your notice in. Who knows what’s happening with unis at the moment anyway

It's a retail job, not a long term career. They realise that most people are probably not going to be spending the next 10+ years of their life with them (particularly with all the people who may have been laid off, who work 0 hour contracts and have no hours due to coronavirus, etc, who they know will probably be wanting to go back to their original careers at some point). Just apply now as full time, no need to discuss you future plans outside of your employment in any specific detail. Once you get nearer to your course starting, you can talk to them about the possibility of going part-time or hand in your notice, as best fits your situation.

I have an interview for a retail supermarket job on Wednesday and they want someone full time. I can do full time for 3 months but then I start uni in January. Should I tell them I start uni in January or should I just give a 4 week notice in December?

It's a retail job, not a long term career. They realise that most people are probably not going to be spending the next 10+ years of their life with them (particularly with all the people who may have been laid off, who work 0 hour contracts and have no hours due to coronavirus, etc, who they know will probably be wanting to go back to their original careers at some point). Just apply now as full time, no need to discuss you future plans outside of your employment in any specific detail. Once you get nearer to your course starting, you can talk to them about the possibility of going part-time or hand in your notice, as best fits your situation.

It's a zero hour contract does that mean I have to do taxes and all that myself even though I won't be making enough to pay tax. What is a zero hour contract?

From what I can tell, having never worked one before personally, is that they don't have to give you any hours, and you don't have to work any of the hours they offer you. They will call you when they have hours available and you will tell them it you want to work them, I think. As far as taxes go since you're on a contract I don't think you'll be classified as self employed and I would guess you are PAYE for taxes on the hours you do work - but you may need to double check that.

I would recommend you learn more about the type of contract for this work before interview so you know what you're actually applying for, as it may or may not suit your needs.