I had the same slippery table top issue so I went down to Bunnings, got a carpet square (rectangle actually) 50 cm x 100 cm and some adhesive Velcro and hey presto, a non slip mat!!

Mine is actually the next size up - the J050, and it fits under my Johnny Mnemonic, Tommy, Jurassic Park, Twilight Zone, Getaway HSII and WH20, as long as it is all the way down. This trolley did come with a rubber mat - but the smell was awful so in the bin it went.