pretty sure to be a leak.
If the radiator is wet along the bottom seam it may be rust in the radiator, which needs to be replaced by new, and the cause (probably a fault in the pipes) repaired.
if it is on the copper pipes coming out below the valves it is probably a bad joint. Sometimes this can be corrected by tightening slighly, but if they have been badly assembled, tightening can crush the pipe and make it very difficult and annoying to fix
If the leak is under the plastic head of the radiator valve, round the tap-spindle, then the valve is worn. This tends to happen with old manual valves that have been turned on an off for many years. Although it is possible to dismantle and re-seal them, it is seldom worthwhile (unless the pipes rise up through a concrete floor and have no movement) so it is usual to fit new. If it is spindle wear, the leak will probably stop if you screw them tightly shut (finger tight only).
Unless you are moderately competent at simple plumbing, best to get an experienced local plumber by personal recommendation from someone you trust (not an advertising website).
You don't need a boilerman for a radiator leak, any experienced plumber can do it. A wrinkly semi-retired one will be fine.
There should be no need to drain the system.
Does your boiler have a pressure gauge?
how old do you think the radiators and valves are?
photos will help.