Shopping list and pictures below are for a single panel antenna , though there will be some material left over, enough to partially build a second panel, so if you are contemplating building more than one antenna (TX and RX pair) or a double or a quad panel make sure you increase you shopping quantities.

Shopping List
https://www.wilko.com/en-uk/apollo-gardening-mesh-91-x-61cm-13mm-galvanised-wire-panel/p/8159832
https://www.diy.com/departments/smart-garden-galvanised-steel-wire-mesh-panel-h-0-6m-w-0-9m/5050642047524_BQ.prd
https://www.ebay.co.uk/itm/304824426774?var=603850298447
https://www.ebay.co.uk/itm/144648261281 enamelled copper wire 2mm 100g (250g = 8.95m, so 100g will be about 3.5m, length need for 1 aerial is 1.5m)
https://www.screwfix.com/p/rothley-aluminium-angle-1m-x-20mm-x-20mm/462JP

2mm enamelled copper wire bent in vice and hammered at corners. 
Tape markers on vice jaw for internal measurements of loops
85mm x 25mm for 1312MHz wavelength loops for GB3EN Receive
89mm x 29mm for 1249MHz wavelength loops for GB3EN Transmit (internal measurements of loops)

Cut wire mesh panel , 17 x 48 squares for a 13mm pitch panel

Mark position of supports punch and drill holes, make middle hole for co-ax 6mm diameter

Insert bolts and mark 27mm up from mesh, mark all bolts the same, cut 2mm wide groove in bolts to the marked line

Fit bolts, washers and nuts x6, not in middle hole

File the ends of the elements to remove the enamel so they can be soldered

Strip some 2mm insulation to make spacers

Fit spacers and elements.  The end of the elements have spacers to raise the wire to 30mm height from mesh, the cross over elements have spacers between them at 30mm height. Cover all element mounting points in hot glue

Twist wire loops around end of elements to secure and solder.

Insert about 30cm of 5mm diameter 50 ohm coax through holes and solder to elements, cover soldered joints in hot glue to weatherproof.  Fit with N connector for TX or F connector for RX