Well since reading this post and checking out the others, I have tried everything from using PS3 ProxyServer, to whatever... Nothing worked.
But I did find a way to install them... Of course it will be a bit long, but for those of you who want to try out the free ones then just try the following:
1) When in your PS3, just create a new user (e.g. UK or Japan)
2) Once created login to the new user account (in this case we will use the UK a/c), and access your PSN menu.
3) You will find that you need to create a new account.
4) Do so but select the country as UK and of course you will need to have a separate User id and a different email address, or you will be rejected and requested to supply a different one.
5) the address can be bogus, as I used.
6) Once created just login and download/install the free Wipeout theme.
7) Once installed, you do not need to keep the new PS3 user a/c, you may deleted if you wish, or keep it till the next freebie comes around.
For AFRIKA and the Japan account be careful as when you create an account the steps will be mostly in Japanese text. If you remember the UK steps, you can go around this, and again a bogus addy is fine.
I have installed both, and they both look good.