I'd avoid Beko like the plague..... I've been happy over the years with Electrolux, Hotpoint and Whirlpool, our current double oven is a whirlpool , and it's jolly efficient, apparently it's a bit different to the run of the mill fan ovens, uses some sort of fast heating element, and more aggressive air movement, it's bloody quick up to temperature, and does a nice even roast.....
to be honest, in the long run, you might be better off putting a new piece of work surface and base unit in there, and fitting a built under Oven and hob...
(if you like em, make it a double oven, singles are bloody useless... ) thus , as and when one eventually fails, you only have to replace that unit, not the whole sodding cooking facility....
for the price of a bit of work top and a base unit, i reckon it makes sense....