Not sure what the SPG rate is, but you can get a 2:1 rate going through Priority Club, and status too.
If you stay at ICs or similar, you could buy Gold for 30 quid, and then transfer 30,000 MR points to PC, which gives you 60,000 points and get Platinum Status!
Then you can transfer the points to BA (and get 15,000 BA miles), and you'll still keep the Plat status.
How cool is that?