Generally conservatories are outside building regs as long as they are within 30sqm, have a separating door, are not used as a utility room i.e no handbasin, toilet, washing machine, are 75% glass or poly and a lintel has been placed correctly above any new opening.

But I would check with your local office anyway. I am sure you will be alright. You don't have to give them your name and address. Just make a general inquiry and have a think.

Kashmir