@Martin et al
Nope although I have done that with other figures.
In this case (I shall post more on my blog in due course) I am either rebasing my Warmaster figures or fixing the base up so that any warping is countered.
The original Warmaster bases are quite thin, about 1mm and have a recess which weakens them further. In some cases, mostly infantry, they have warped so badly that the bases spin on the tabletop or have even snapped in two.
I have replaced those bases with 2mm plasticard based with magnetic tape and magnetically stuck to steel paper while the glue dries to minimise any new warping.
On some of the Warmaster bases I have simply glued another 1mm plasticard base underneath complete with underlying magnetic tape and I will fill the gap between the two with modelling paste.
At the end of the day each base will be substantially thicker than before as well as being magnetic. I will be keeping them in a steel paper lined box.
I might even get some more gaming done with them.