Hi Colin,
I'm currently building a SER Kits 'O' Class, albeit to Scale 7 standards., which has necessitated me scratch building some parts of the kit, notably the locomotive main-frames.
However, concerning the etches I have used, they are well designed, and fold up easily, where necessary. The written instructions are easy to understand, and should you encounter any problems, the proprietor of SER Kits, Dan Garrett is very helpful at offering advice and suggestions if difficulties are encountered.
Wheels and motor have to be purchased separately, but Dan points you in the right direction as to what is required.
I'm so pleased with the kit, that I am shortly to place an order for another 'O' Class 0-6-0 and an 'A' Class 4-4-0.
I hope this information is of some help to you in making a decision.
Dave