Armoured cable

Grenage

You're going to do this yourself regardless, so I won't add to the above.

Make sure the cable is to a sufficient depth for the full run, and adequately protected. I think it's normally 4-500mm so a spade won't hit. Surround it with pea shingle.

The cable will be fine; it's worth getting someone canny to check the terminations. If you're selling the house then you'll need to remove it or declare it.

Heedtheadvice

Oh dear!

OP you do seem to have missed the best advice 'notifiable' and 'get an electrician'.

"What is 'notifiable work'?
Notifiable work is a term used to describe particular types of work that are subject to compliance with Building Regulations notification or approval.

Work that needs to be notified should be signed off by your local authority building control body. Alternatively, you could use a registered competent person who can self certify that the work is compliant."

Are you a registered competent person?

Note there are minor differences applicable to Scotland and Northern Ireland but that should not really affect the requirement to be competent. Can you prove you are competent?

Heedtheadvice

....and there is more to it than Greengage suggests!!

seatbeltnoob

You can understand why electricians and other tradesman dont describe exactly how they are going to do things in detail. Because just as OP demonstrated they're just wating the leccys time picking the brains and then doing the work themselves.

Maybe if you're honest and ask an electrician for advise they'll be able to come and give you the details of how to carry out the task for a reasonable fee.

Ectophile

If you're going to do it yourself, learn how to terminate SWA properly. Don't just hack the armour off at both ends and think that will do.

Owain_Moneysaver

And motor start current and supply impedance may make some lovely differences to the calculations.