I've got help from F1 dedicated forum. Apparently there were 2 more screws at the top of rear wheel arches.
Following an advice from F1 forum, I've removed rear tires from the wheels and that opened access to those hidden screws.
After that block was removed I was able to dis-assemble the rest of it with pretty much no issues.
It turned out to be a decent model with high level and accuracy of detail for a die-cast. There will be a lot of things that would
have to be improved and converted to specs of racing car. But it provides a decent starting platform, imho. This is my "dream"
project. Hopefully I will be able to make a reasonable conversion into F1-GTR from LeMans 1995 over next number of years.
Here are some photos of the process.
