1980dhc,
Yes, the Mustang II front end has been swapped on many different cars here in the US. The TR7 front suspension is good, especially if you do the following upgrades which will be much cheaper that the fabrication you will have to do to fit the Mustang II assembly.
New tie-rod ends, ball joints, all poly bushings & anti-dive kit available from John's Cars.
http://www.johnscars.com/tr7/tr7new.html
Roller bearing kit from Ted. (He is bringing out a strut tower kit for the TR7 which includes new springs.)
http://www.tsimportedautomotive.com/
Gas cartages available from many suppliers including John's Cars.
The Wedge Shop has front brake upgrade kits and will make you a modified Ford rear-end that will drop right in to the TR7. Don't forget his custom proportional block when you upgrade the front brakes.
http://www.thewedgeshop.com/triumphhomepage.htm
Some people here have built adjustable coil over front struts. If you go that route, you can use the bottom half of the strut housing from either an SD1 or Land Rover (can't remember which) that has a bigger spindle and hub assembly that gives you a 5-bolt pattern.
Have fun, drive fast & safe, be kewl,
jclay