This is a guest post by AndrewM following his enlightening email.
I was looking at Ofcom’s recently published Digital Television Update/Progress Report for Q4 2008 (press release: http://www.ofcom.org.uk/media/news/2009/04/nr_20090406a – overview with link to full PDF: http://www.ofcom.org.uk/research/tv/reports/dtv/dtu_2008_04/ and I noticed that in these reports they not only give the cumulative number
of Freesat unit sales figure for each quarter, they also say how many of the Freesat products sold are HD-capable. Looking at reports for Q2 and Q3 as well, I realised that from this information I was able to piece
together the complete picture of how many SD and HD units were sold in each quarter.
Note that Q2 figures have been rounded to the nearest thousand, and the percentages of HD equipment have been rounded to the nearest whole number. The original Freesat sales figures that I used to do the sums (Ofcom don’t lay it all out in a nice easy-to-read table, some math was required ;)) are found on page 15 of each of the reports.
Freesat unit sales – 2008
Q2 2008: 39,000 units (15,000 SD and 24,000 HD) (61% HD) 
Q3 2008: 69,000 units (20,000 SD and 49,000 HD) (71% HD) 
Q4 2008: 125,000 units (26,000 SD and 99,000 HD) (79% HD) 
Total sales for 2008: 233,000 units (61,000 SD and 172,000 HD) (74% HD) 
 http://www.ofcom.org.uk/research/tv/reports/dtv/dtu_2008_q2/q2_2008 [sic] (for some reason, they didn’t add .pdf to the end of the file name)
It’s interesting to see that the number (and proportion) of HD boxes sold has increased so much, just about doubling every quarter (although I don’t expect that to continue into Q1 2009 of course given the distorting effect of Christmas on Q4 sales).