There is nothing to find at the posted coordinates. Apart from a lovely park!
The code can be obtained by completing my Adventure Lab "Alexandra Park - Having a Lark". You can find further detail about the App for Adventure Labs here: https://labs.geocaching.com. If you already have the App then search on nearby Adventures to find it.
Direct link to the Adventure
Answer 5 questions and enter the code made up of letters and numbers into the Certitude checker. The final coordinates and hint will become available to you.
You can validate your puzzle solution with certitude.
Just some Admin details about the park
The park entrance for cars is at the top of Shakespeare Avenue at N51 22.420 W02 21.660
The park is open between dawn and dusk for pedestrians. You can park your vehicle there between 9am and 3pm although there are no gates, so cars can always get out. According to the website, there are no cars allowed on Sundays, but I haven’t seen anyone policing that requirement. Carparking on Sundays is allowed on the surrounding roads.
Parking inside the park is available for up to 4 hours. The FIRST hour is FREE but you will have to ‘pay by text’ to even get the free hour. Send the work ‘PARK’ and your registration number to 61600 i.e. PARK A123BCD and Quote location 751079. There are numerous signs explaining. There are a few car parking spots on the road at the top of Shakespeare Avenue (some free for 2 hours), but please beware of specific local permit instructions.
There are unisex toilets just at the opening of the park but you will need a 20p coin to access. Dogs are allowed off the lead in the park but not in the childrens play area.