Could this method work?

I suppose this technique is just a form of DILD, but I'm not sure whether it can actually work.

A good amount of my dreams often take place in one of the two schools I attended in my youth, but normally the first one in particular. I no longer attend school and never visit the place.

Would it therefore be possible to train my subconscious mind to reality check every time I find myself at school? On one hand, it seems very logical, but since I no longer go there, I can't really train myself to RC when I go there. Is this something that could be practised purely in my head and made to work? I feel like this could be very effective for me if I can nail this down.

Yes, this is something that can be practiced in your purely in you head and made to work.

Plan to do a reality check at your school. See it happening. Tell yourself this is possible and that you're going to make it happen. Then, fall asleep waiting until you find yourself at school. If it goes to plan, great! If it doesn't go to plan, think about where your attention was when you were aware of your school and then think about where it should have been.

This will help you build lucidity inducing self-awareness in your school dreams.

Yes, I also do that, and it sometimes works rather randomly. Essentially, your school is a dream sign.

Its interesting you said that because i dream alot about bieng on holiday and yeah i got like twice a year but i also am thinking of a way of training my mind to remember to RC during a holiday dream

your school is something very specific that is good. visualize/incubate different scenarios that include your school and how you get lucid because of some hint. make it as realistic as possible, insert all your senses. do this maybe two times for 10min or as long you want. one time might be good if it is right before going to bed/falling asleep.
this will have two advantages: on the one hand you probably will dream more often of your school because it "bothered" you during the day and on the other hand you set your intention again and again to get lucid when you are at school so you will be like ah at school again.... wait... this is a dream ;)

Thanks for the help guys. Will experiment with this. Got pretty high hopes!