I looked in my aircraft folder and found a CRJ700 and a CVA_CRJ2_9. The 700 is the default and it has those lines for maxbank. I changed that one first before I realised the CRJ2_9 is the CVA 200 for FSX - but it has the following lines re bank:
max_bank_acceleration=1.800000
max_bank_velocity=3.000000
And by the way, the 700 had maxbank as 30,15 as in:
max_bank=30,15
max_bank_acceleration=1.8
max_bank_velocity=3.00
Duh - I guess I just need to add the missing max_bank=30,15 line!
Yup - works perfectly. Thanks.