Rapido have announced than the 04 is on hold for now in their newsletter.
"BR Class 04 Shunter
Another project that will be paused is our 00 Gauge Class 04 shunter. Several reasons have caused this project to slow. The primary reason is a lack of access to original drawings, which we have found almost impossible to source. We pride ourselves on producing the highest quality models, that are as historically correct as possible, and this just isn’t something we can guarantee without appropriate drawings. One archive told us they held a set, and then subsequently took 6 months to obtain a copy – only for us to find out they were mislabelled and were Class 08 drawings. A frustrating disappointment to say the least.
We currently still cannot find the primary drawing information we need and have concerns about how this impacts the number of class variants required to make this project viable. So, we have reluctantly decided to park it for now. Never say never, as we can still go and measure and laser scan the surviving locomotives in the future."
Refreshingly transparent communications when issues are encountered!