Hi sorry about the delay. Here are a couple of the original pics from 2016 showing wheel swaps on Lledo vehicles.
Model T van:
Peugot:
All the Lledo wheels are a standard 14mm diameter. For some of the larger models they just look wrong . The Matchbox MOY models can be bought in junk condition in job lots and the spoked wheels vary according to model from 16-19mm. My method for swapping them was a bit clumsy back then but you get the idea.
For later vehicles when pneumatic tyres came in I struggled to find good wheels but then discovered a great source- Stuart Binning from Anyscale Models. After an email he kindly supplied me with resin wheels from his range in lots of different diameters. He has recently added separate wheel sets on his web page.
Here are some conversions and the difference they make to diecasts:
added to a diecast Unimog which had very toylike wheels:
Model A van "militarized". These diecasts are so plentiful I pick them up for 10p at car boots!
1934 Chevy van as in the original poster's pic. This looks much better with 16mm resin wheels compared to the original 14mm Lledo wheels.
Hope this helps anybody.