Thanks for the info - and thanks for the summary as I'm afraid I can't make head nor tail of legalese!!
Briefly, that means as follows:
1. L cannot refuse/delay consent to an alteration that improves the property.
2. L cannot charge a lump sum fee.
3. L can charge only its properly-incurred legal and administrative fees for issuing consent.
With regard to point 3 - could they not argue that this charge (£300) is to cover their costs for legal and administrative fees?
If you could advise me on the simplest and easiest way to proceed I'd be very grateful. (obviously I'd prefer not to pay the £300 but would do if it's all above board and legal... it's just that I get the feeling that they're trying to see if they can make some easy cash out of us.....)