Wages might go up
The minimum wage is get by the UK government.
Result: Neither
Unfortunately employers tend to pay people as little as possible, especially when the cost of goods will continue to rise.
So even if there is less "cheap labour" from EU immigrants, it just means there will be more vacancies for those low paying jobs - of which there are plenty of vacancies already.
This includes farms (seasonal work), hospitals (nurses), hospitality industries (hotels, restaurants, shops), etc.
For a 52 hour week, the minimum wage should be closer to £10 an hour (source).
And without guaranteed working hours (i.e. zero hour contracts), should be paid closer to £20 an hour - because they are responsible for sick days, holidays, pensions, tax returns, etc.
If you disagree, or would like to add more details, please let me know.
You can suggest a reason for leaving the EU, or look at the other reasons.