I know this is a silly question, but to replace a gas hob with a new
one. Do i simply turn the gas isolator valve next to the cooker to
off(this is in the kitchen cabinet under the worktop below the
boiler). Once ive removed the cooker which i'm also replacing, can i
simply disconect the gas supply from the hob?

Ive obviously isolated the cooker circuit before doing this, but if
the gas fitting on the hob is situated in a different place on the new
one, can i use copper tube and compression fittings to extend it?

Ive seen people say only to use solder fittings, but is this really
neccessary?

Also if I can use compression joints is there a substitute to PTFE
tape?

Also when i disconnect the gas there will obviously be gas in the pipe
from the isolating valve to the hob, any problems or recommendations
with this?

thanks......