You could buy an RCA to aux cable and the T20's, as they're still a decent choice for the price, especially for someone with limited space as they have a small footprint. They sound pretty decent and are inexpensive, but they're not as quite a good as buy as they once were, unless small as possible is required. For around £30-40 more, the aforementioned Wharfedale 9.0's + small amp offers better sound quality.
I suppose it depends on what you want the speakers for though. If you want a decent speaker for music when you don't want to use headphones, then the 9.0's are certainly worth spending the extra on over the T20's. If you do all your music listening with headphones though and just want some general purpose speakers, the T20's are a decent choice. Cheaper overall and easier to place if space is limited.
Depending on what you want to use the speakers for, there are some alternatives; such as Edifier R1280T. Same size and similar price to the 9.0's + SA36 amp, but active/powered speakers; so you'd connect to mains and the DAC. Personally, I'd take the 9.0's + amp, but the Edifier's are a good alternative for those who want speakers without having to have a separate amp.
If fitting in speakers the size of the 9.0's is going to be a stretch, M Audio AV32 is a smaller alternative, although not by that much really. Smaller 3" woofer, compared to the 4" in the 9.0's. Bass will likely go a bit lower with the 9.0's though, because the larger size.
