SNSGuppy,
Of course anyone can use airways designated points if they are convenient but they may obviously not be, due to airspace constraints such as danger areas or other controlled airspace beneath them.
We may be separated by a common language but in this part of the world an IMC rated pilot is restricted in what he/she is allowed to do. An IMC rated pilot cannot enter controlled airspace under IFR. Airways are Class A and therefore require flight to be conducted under IFR. Special VFR is allowed in CTZs but not in airways.
An IMC rating extends the privileges of a PPL (A) holder to allow flight as PIC:
* Out of site of the surface
* In a control zone on SVFR clearance with a flight visibility less than 5 nm but not less than 1.5 nm
* Outside controlled airspace in a flight visibility less than 1.5 nm
* Carrying passengers above 3000 ft amsl in IMC or in flight visibility less than 3 nm at or below that height, when outside controlled airspace
* During take-off or landing with a flight visibility below cloud of not less than 1 nm
The IMC rating is only valid in UK territorial airspace, Channel Islands airspace and Isle of Man airspace.