Can you operate numerous trucks out if different
Locations with just one ol ?
Yes, if they are in the same traffic area.
We do.
We park our vehicles in 4 different places. That doesn’t mean it is right though, not having seen the O L details 
If all your operating centres are in the same traffic area, then I’m sure they only need one o’licence, but you will have to apply to use each operating centre, however if they in different traffic areas then you need another o’licence to cover that area.
Provided you’ve got a licence and are doing everything else properly it is very unlikely to be picked up on provided they are parked up on an industrial estate where they’re to be expected.
I know of a few that have drivers covering local regions that just rent a parking space wherever’s closest to where the current driver lives and don’t think they do bother doing it properly. Having said that the trucks do frequently go back to base for inspections and to pick-up/deliver loads several times a week.
Personally I would favour doing things right but if there’s work to be done right away I might be tempted to crack on as it’s very low risk if you’re sensible.