Weak signal

[Moag]

Hi there, had Sky broadband now for 9 days. Guaranteed speed is 55.6 Mb/s, but I'm only getting 37 to 38.6 Mb/s, after checking speed 3 times. Would just like to ask our community here if this is quite normal, as they did say they'd do tests over 1st month. Any advice I'd be most grateful and Thank You first of all.