>when I pop to an appt somewhere, or to the shops. Would you say this is sufficient
Depends on the area, and the attractiveness of the bike. But it's a cumbersome carry for weak security, and you might do better to buy a small, very tough disc-lock. Much easier to keep under the seat or in your bag, more resistant to attack, and you can use it for home lock-up too. Examples -
https://www.amazon.co.uk/Kryptonite-Evolution-Lock-Black-Disc/dp/B0030LVA28/
https://www.amazon.co.uk/Kryptonite-Evolution-Compact-Lock-Orange/dp/B07B4GF1G9/
In the short-term, any reasonable chain is better than nothing so don't chuck it out.