I've been following @ravenstar68 's advice and my Desktop is clear through the wired ethernet connection. I've ordered a Wifi dongle to complete the testing and in the meantime I've switched off my IP cameras as a precaution a few days ago, although i'm still using my iphone and ipad.
Do you think i should disconnect those devices too while i wait?
To be honest unless you have jailbroken the iPad and iPhone and installed something from a less than trustworthy source, the chances of you having malware on an iOS device is quite small. Apple's vetting of software in the App store is not perfect (nothing is) but the chances of anything malicious being accepted and then you happen to have installed it is low.
The Spamhaus lists are dynamic - they are updated regularly, so that when malicious traffic stops, your address is de-listed. If it starts up again (after a device or the spambot itself has been dormant), then the address is listed again.