I'll be buying direct, myself but Hooben already has several dealers in the UK & another pending in Germany:
Antics Online:
http://www.anticsonline.co.uk (Hooben's RTR Perkasa is currently listed, T-55 was shown in the tank section but pulled pending release)
Vosper-Perkassa
http://vosper-perkasa.com/estore/index.php? (Hooben's RTR Perkasa listed; not sure if they'll carry AFV)
AFV-Model
http://www.afv-model.com