I'm sorry, but you will probably struggle to get a piccolo that is worth having for £200 - even on the secondhand market. The piccolo is a harder instrument to play than the flute, and you will struggle if you are having to fight against a poor quality instrument. It is generally a lot harder to get a good sound and accurate intonation out of a picc compared with a flute, and the cheap instruments tend to have problems in both these areas. A piccolo is not simply a mini flute - the embouchure is not entirely the same and there also some differences in terms of what you do with your diagphragm because the piccolo exaggerates things like vibrato.
The YPC-32 is generally regarded to be by far the best starter piccolo (and I say this as someone who doesn't really like yamaha instruments). It has a good mechanism and has a resonably reliable sound across the full range of the instrument. Although intonation can still be problematic with the YPC-32, it is generally better than with other starter piccolos. However, as you have persumably noticed, these retail at over £200 on the secondhand market. I have heard good things about the Pearl grenaditte piccolo (although I've never played one myself) - but I think you'll find that these are more expensive than the Yamaha YPC-32 and as a newer instrument there are probably less available on the secondhand market.
I don't paticularly like the tone of the YPC-32 (and also don't generally like the sound of yamaha flutes). I started with the headjoint supplied but now use a wooden Philip Hammig headjoint instead of the yamaha one, which gives a much richer sound in the lower octave and a sweeter sound in the top octave. However, this is a more expensive option than the basic yamaha because of the additional cost of the headjoint and the cost of getting the instrument regulated to the alternative headjoint. It is probably best to use the headjoint supplied to start with, as these are fairly easy headjoints to play (plus they have a lip-plate similar to a flute, which a lot of piccs don't have), and then once you're more competent think about upgrading.
Good like with your hunt.