Supply 7403 style shelf (50.8cm/20” deep) to your size specification as follows:-
1 x 845mm neat (wall to wall). So, 840mm so that it does not scratch the sides.
2 x 795mm neat (wall to wall). So, 790mm so that it does not scratch the sides.
Charge to supply and labour to cut to your sizes as above will be £83.64 + VAT
Delivery to G74 5HD £25 + VAT.