You can buy all in one alarms and defense sprays. Mine makes an ear piercing should, spray a foul oder, and coats the attacker in UV gel.
More and more free self defense classes are popping up so it is worth hitting Google.
I also recommend a light backpack with the following.
A mini first aid kit
A torch
Your phone and a portable charger key that you can pre-charge
A fiver and some 20p coins
A cereal bar
Some water
Flip flops
A towel
Some tissues
And those time of the month essentials.
That is my kit. I dunno if I am running or looking for One eyed Willy's gold.