Double oven built under. Mad idea?

Hi folks,

Here’s the background:
My kitchen is very tight for space, and the only place for a cooker/oven is where I have a Creda cooker at the moment. This is OK but really getting on – must be well over 10 years and is “well worn”. I don’t have enough money to get a really decent brand cooker and good second hand built-under ovens are like hens teeth.

I’ve got in into my head that I could get a good s/h built-in double oven, which are fairly easy to get hold of right now, but use it as a built-under, with a hob on top. The work top would need to be 30 -50cm above usual height to allow for required clearance, but I don’t mind too much how it looks, as long as it is safe in operation.

I’m handy enough to do make a suitable, custom built unit to fit and match cosmetically with the other units already there (but there won’t be much showing anyhow).
I don’t have gas, so electricity is the power requirement.
I’d use a qualified sparks to make any power supply/wiring changes needed.

My questions:

Is this a completely daft idea?
Would the existing mains supply for the cooker be likely to be sufficient to run a separate hob and oven (with a spur and additional cooker switch appropriately fitted by a qualified sparks)?
Am I right in think a cooker will have about the same power draw as a oven/hob combination

Any suggestions/comments welcome..