built in electric ovens

[maitre d']

We're planning to make-over our kitchen.  Any advice on fixing a built in oven.  It's going into an existing cupboard.  Should we vent it to the outside?  there'e some wiring in the cupboard, will this need some protection?  The new oven will be at chest level, would worktop thickness chipboard be suitable for it to stand on?  Can you slide them out if something goes wrong at a later date?  Is it OK to wire it myself or do you need an electrictian under the new regs? {Cooker circuit alreay in place nearby] I'm in the UK