Anna
I was intrigued too, to read only 23 swords were awarded at Trafalgar.
A little bit of research has led me to an interesting website,
http://www.lloydsswords.com which could give us the explanation. In a sub section entitled 'Background' on the site, it lists the various sword types/values produced and the £100 Trafalgar sword is recorded at 23 as stated. (It lists in total 165 swords produced and which were awarded for other actions). It goes on to say that officers could receive a piece of plate instead of a sword or indeed an award of cash. In some cases this was for charitable purposes such as distributing to wounded crew members or just to keep the money themselves. I presume then that this choice was made by some of the captains at Trafalgar.
However a little further down on the site there is another table with a more detailed breakdown which slightly contradicts the figure of 23. It states that 25 were Awarded, 23 Recorded, with 2 Not Presented. (It also advises that 21 have been traced). Perhaps awards were made in advance of actually producing the sword, giving time for the recipient to choose an alternative.
It's an interesting site which I will certainly return to when more time allows.
I hope this explanation is helpful.
Regards
Phil