Last few qtrs, taken from my spreadsheet (yes, I am that sad);
21000 (just finishing)
34050 (J&J, TV brackets)
10700
11500
13400 (about a 'normal' spend qtr)
15050
34200 (the qtr with the '1200 CC on a case of wine, no min spend'. I love Lambrini )
24150
18600 (When I discovered Flyertalk)
2000 (err, that's a guess.....)

So that's about £1800 of vouchers, exchanged for >400,000 of BA miles, without a hint of Marriott points or anything like that. I keep a few to pay for the RAC membership, but all the rest got to BA.