Be aware that Costar stabilizer inserts are glued into the stabilizer posts of these keycaps. Removing them for use with other types of stabilizers (e.g., Cherry) could be rather challenging.
I have these and they are very easy to take out.
I'll get my photos ready and post them here from the whole process. They have some simple soft gel-like glue there, you can easily pull them out with screwdriver or something flat.
Pity they not coming up in UK, I would buy another set of theses.