Quite possibly.
To reissue the crutches they would need to:
Book them in.
Give them an inventory/tracking number (so the following could be done properly)
Check/replace rubbers (that can be "fun", they are usually extremely tightly fitted).
Check the various rivets are in good shape (there are several that wear/work loose).
Check the arm ring and handle grips are good (the grips have a tendency to shift/work loose).
Clean them (may require dismantling).
Store them.
Document all of the above as having been done by someone with suitable training (and likely done off site as I doubt the NHS has the room/facilities at most hospitals, so that's added costs).
You can buy better crutches than the NHS typically supply for under £30 retail if you know where to go (I used to have to do it for my mum*), and for the NHS to reissue them and be covered for insurance liababilities it would probably cost more than writing them off after one use of several weeks/months.
Wheelchairs tend to be far better constructed than crutches and typically far far more expensive

(we were lucky to find a local retailer that did them for only about £250, after one scheme** that issued my mum with one via a voucher ended up costing us about £300 on top of a £300 or £500 voucher).
In my experience crutches only tend to last about 12-18 months of use anyway (that was with my mother using an electric scooter for any movement around outside), so any savings would likely be minimal allowing for the cost of the refurb/reissue.
*She was on crutches continuously for about 20-30 years, and it would take months to get replacements via the NHS vs about 15 minutes online, or a 30 minute drive.