I agree something probably needs to be done about it - not sure why PeteFrench was allowed to keep his registration to spam again, or maybe he simply re-registered.
Maybe there ought to be a restriction on the number of new threads that can be started by any individual say in a 24 hour period e.g Two, which should meet the needs of most genuine users? That would both limit the amount of spam and should act as a subsequent disincentive to spammers as they generally seem to post multiple messages.