This is a cheap mode.
There is no structural problem, but the sound quality is low.
I think you should upgrade to Yamaha U1 after grade 6.
Hong Kong is a free market, new and good thing always expensive. So, you can find really good stuff at low price only in 2nd hand market. I suggest not in 2nd hand shop or warehouse, but from auction place because seller is the owner of a piano. He/she sells piano not mere for profit making.
Here are the sites maybe helpful:
hk.auctions.yahoo.com
www.go2hk.com
www.ebay.com.hk
www.red-dots.com