From the manufacturer:
These reproduction panels are just as originally fitted to all UK build Mk1 and Mk2 Mini saloons and travellers with a design of 8 horizontal lines formed in the top of the panel. We create this with a high frequency welding machine and our own dedicated tooling; the original appearance is achieved by using the original factory method. The material used is very close to the original specification which on all the main production run Minis between 1962 and 1967 was quite coarsely grained, and which is available in a number of the most popular colours.
These panels will look their best if new fillet panels are also fitted in conjunction (DP3022).
Special order, lead time required. Additional colors may be available; actual colors may vary from those shown.