The wrist will be painful:
o Tendons can actually stick to their sheath thro lack of use
o Laying bricks involves a heavy mass, high flexion, *repeated*

You could...
o Ask for an NHS physio to provide some exercises
---- the consultant could have done this (not 2 fingered variety)
o Ask a private physio to provide some exercises
---- 1 visit, simple charts of exercises first explained to you

The biggest problem in physiotherapy is patients not doing it:
o Rubbing a cream on your leg whilst in the packet doesn't work
o The patient has to follow very BORING exercises, done right

If the squeeze ball is a non-linear foam which doesn't snap
back sharply (ie, like cheap polyurethane) it will work ok.
Otherwise it may aggravate the injury - same reason why they
do not put cheap foam on ejector seats, only E-A-R ConFor foam.

Alternatively:
o You could do a google search for rehab exercises
---- depending on your injury this may work, or may not
-------- few physios give visual advice online in USENET :-)
---- altho many standard exercises could be video on a fee-for-access
-------- without indecypherable thick indian insurance selling accent :-)
o Finding a decent med library, physio book & looking up your injury
---- patient self-diagnosis is a dire solution
---- however, you are in the diagnosed outpatient rehab category

A private physio can draw up exercises in 1 visit (£25-40).
They may try to get a revenue stream from you, but they really should be
able to 1) recommend some decent exercises 2) give sheets showing them.

A physio of course can use other treatment - interfential, physical
manipulation & mobilisation, ultra-sound, and so on to speed recovery.
TENS is not interferential, TENS is often a 9V-powered-placebo so do
not go in that direction necessarily for over-the-counter pain relief.

Amusing this is in a uk.d-i-y group vs a medical newsgroups :-)
"NHS hip replacement patients seen posting to rec.metalworking"