chapsmum, are you a doctor, and if so, are you an orthopod?
Actually, the treatment of ACL tears in the UK is comparable to that in the US. Plasters are rarely used, and many units do ACL reconstruction as Day/ 23 hour surgery. MRI is used, preop, to determine whether the ACL injury is complete (it is not always possible to tell by examining the patient, especially when the injury is relatively fresh), and to help plan the surgery (if meniscal repair/ resection is also required, it can add a lot of time onto the operation; if the patient is having a spinal, which can wear off in 2 hours, it is important to know). In our unit, a routine MRI will take 7 weeks, it can be requested sooner if the surgeon feels it is clinically warranted.
Some TA ruptures are treated with plaster, some with surgery (results are equivalent and complication rate is a bit lower with conservative management). Those treated with a cast are treated with a below knee cast, not above knee.
Scaphoid fractures are treated depending on the displacement, with surgery or bracing. If a cast is used, the thumb need not be included, as it does not improve healing rates. Some casualty depts still apply scaphoid casts, but most fracture clinics would remove them ASAP.
I'm rather cheesed off that you see fit to run down the NHS, when you clearly have a very outdated view of how we work!