A little research reveals that the 'Echo Charlie' pirates use LSB rather than USB. Thus interference should be less - although there would still be some artifacts and garbling which would cause poor reception.
The 6 MHz pirates in London used AM; that was far, far worse.
One of the plus points of NFM CB was its interference immunity; the illegal (in UK) AM system was far more intereference prone and the use of linear amplifiers to drown out other transmissions posed serious risk of interference to lawful services. Early Tornado operators at Cottesmore were concerned that truckers on the A1 'wearing boots' (using linears) could cause UCMs to be induced in a/c on the approach over the road....