Technical Spare Wheel and What size Wheel Brace do I use?

[qwerty2018]

I have a 20 year old Fiat Punto 1.2 and had it for 8 years now. I was driving along and got a punture and got to a garage and they took my wheel/tyre off and put my spare wheel/tyre on for me. A few days later got the original wheel trim from punctured tyre and got a part used tyre put on and put this back into my boot as the new spare. My questions are - had car 8 years and never had a puncture before but put spare tyre on and no idea how old it is as it came with the car then 12 years old when bought but wonder if it is ok to keep this spare on full time. Also no idea about the wheel brace i need as admit not car savvy mechanic wise so if this puncture happens again I could be in trouble.
Seen both Euro Car Parts and Halfords have the following:

Streetwize Wheel Braces (GS Tuv) - Blue- 17 x 19 x 21 x 23mm | Euro Car Parts

Streetwize Wheel Braces (GS Tuv) - Blue- 17 x 19 x 21 x 23mm at the lowest UK prices from Euro Car Parts UK’s No.1 for Car Accessories, Car Styling & Car Care. Buy today Online, In store or by Phone + Branches Nationwide – Next Day UK Free Delivery.

www.eurocarparts.com

Halfords 4 Arm Wrench Wheel Brace | Halfords UK

Shop the latest The Halfords 4 Arm Wrench is a heavy-duty 4 way wrench with 4 sockets to fit most wheel nut sizes. at Halfords UK

www.halfords.com