Postage through myhermes and parcelforce insured have both worked fine for me, sending and receiving.
The only issue I’ve had recently was when buying a set of forks off ebay, they arrived, looked fine, but on stripping the lowers off for inspection they were absolutely goosed with snotty oil (on one leg, none in the other) and heavily scored stanchions. Luckily the seller was apologetic and great with the return.
If buying always drop the lowers and inspect ASAP upon arrival, and if selling, make sure you’ve stripped, inspected and photographed should the buyer want to be awkward about anything like that later on.