Meaning of "radio rental" ?

I was reading this currently locked thread about an individual going by the name “cyclotouriste.” Zabali Clawbane points to an article in The Scotsman with more information about cyclotouriste. Here’s the paragraph I have questions about:At the time of publishing I have received no reports of any female, healthy, cyclists with a sense of bold adventure signing up for Cyclotouriste’s magical mystery tour. Now, normally this would just be chalked up at some guy having a bad day and going radio rental on a message board . . .

What does “radio rental” mean? How common a phrase is it? Thanks.

From context, it sounds like their version of “going postal”.

Rhyming slang: Radio Rental = Mental

(Radio Rentals is an electrical-goods retailer)

Damn rhyming slang, I never get it.

[Don Cheadle]If 'e goes radio rental you blokes’ll be in Barney.[/DC]

Radio Rental(s) was a company where you could out rent radios sets. This was in the days when the things were very expensive to buy.The company then branched out into TV’s and domestic appliances. With the advent of very cheap electronic goods the company finally closed down about five years ago.