Get some silicone base glue:
https://diy.evo-stik.co.uk/product/serious-glue
Available from the DIY sheds, this is NOT an impact adhesive, but a slow cure silicone, strong, flexible and sticks to most things. Great for gap filling applications or if you need a bit of flex.
If you google 'pickup pole piece' you can restore your old pickup too, for a few quid.