Like Linden (above), I am hoping Ken has time to respond again on this.
To Largissimo- no advice re the merits of different manufacturers, but some shopping suggestions. There are actually two Ecodear alto models. Early Music shop only sells the YRA-402B which suggests to me it is the better of the two. Yamaha also sell many of their models in German fingering versions as well as Baroque. The Ecodear YRA-402B and the 300 series models are both described as ‘Rottenburgh’ which suggests they are very similar. However, the Ecodear tends to be £10 cheaper!
If you are not price sensitive it’s nice to get all the contenders on approval from EMS (if you are in UK). They charged me £10 approval service + about £9.50 postage for three plastic trebles and it cost me about £12 to send them back Special Delivery. EMS is an expensive shop compared with (say) Amazon or Thomann so I ended up paying a bit extra for the recorder I chose. So it cost me more than the price of the Ecodear, just to try a few out! Personally I thought it was worth it for the experience and to avoid amassing too many plastic recorders. A more price conscious alternative is Thomann who do a 30 day money back guarantee.
Descant and treble recorders.