That seat map was for the flight from DXB-GLA which will possibly suffer more from connecting pax hence the advice to pay for seats. When I looked at the seat map for your flight from SIN there were still quite a lot of open seats but didn’t realise that the flight came from MEL first.

Have you paid for seats on both legs? Due to some technical issues with FT at present, I’ll post a screenshot of the current seatmap for your SIN-DXB flight in a separate post. Note that I haven’t managed to get the first few rows in the front Y cabin in the screenshot but these are either already selected or blocked by EK.

S