It is your right NOT to disclose after 5 years and I would say not to. You can obtain your record from the CRB to see what it says. I think you only need a basic disclosure for an airside pass and this is what most employers get - it will NOT show your conviction when it is spent - so DON'T offer the information. Do your homework before any application as there is an advanced disclosure that people like police etc have to give and this shows everything, spent or not, remember things might change with security around aviation.
In the mean time get your PPL etc and get some hours in and build your CV - make yourself attractive to employers, by experience, qualifications etc to stand a chance of getting that job, yes in 5 years time.
Remember if you apply for a job before your conviction is spent you MUST declare it. If the employer then turns you down and you go back to them after your conviction is spent, they still have it on their records - what to do then????
Good luck and don't be so stupid again.