Mastiffs are big but the JLTV is also pretty huge. Its made even bigger by the fact you can raise or lower the suspension, so if you see them doing some serious off roading they're huge.
Which blows my mind as I thought modern vehicles were supposed to be getting smaller whenever possible and not bigger!
At first I had doubts as to size in relation between a Mastiff and a JLTV models but looking online when comparing them to troopers standing beside they look spot on.
Personally thought because the JLTV is supposed to replace the Humvee it would be a similarish size but apparently not. I look forward to seeing one in the flesh as the British Army is supposed to be buying them.