Blemain finance unfair charges help!

I took out a Blemain finance loan back in 2005 for £16.913.00 , secured against my property (it was actually a refinancing of a previous loan with First National Home Finance) . I sold my property in Jan 20012, so both the mortgage and the Blemain loan were paid off. The interest on the loan was 12.2%

The final redemption payment to Blemain was for £23,253.36 in Jan 2016 and this was paid in full.

I got the SAR from them so i have a break down off all the charges. Through out the loan I did have money problems, looking at the breakdown of my account there is quite a number of late payments.

There's just a few things I could do with help on:-

Over the period of the loan I've been charged for:

Letters = £30 - £35
Visit = £100
telephone charge = £30 - £35
Monthly charge - arrears = £33 - £46
Dishonoured Receipt = £30 - £35
Default Notice = £50
Buildings Insurance = £85 - £184
Buildings Insurance Block policy Charge = £16
legal costs = £282
application to suspend legal action = £13
settlement figure fee sent to 3rd Party= £30
Court preparation fee = £53
court hearing fee = £13
land registry copies =£4
online issue fee = £100
Issue warrant for possession = £18
collections instruction = £176.25
Legal fees to HMCS = £150
Post - Legal monthly Charge 2 = £130 - £215

I did get close to getting the house repossessed twice, which is why i had to sell it quickly and under the market value.

Some of the above were charged multiple of times, others just a few, All in all the total charges come to £5,865.50

plus there was a Broker fee at the start for £1,500 (this is not included in the £5,865.50)

1) the £1500 broker fee seems excessive, is there anything that can be done? Are they allowed to charge that much?

2) Which of the above charges can I try to claim back for? bearing in mind they did attempt to take me to court a few times fir monies owed, this was during the time I was trying to sell my house as i couldn't afford to live.

3) I have downloaded the CIsheet (compoundinterest calculator) and entered all the charges.
Bearing in mind the loan interest rate was 12.2% APR what % do I put in the interest rate (Apr) column, is it the APR of the loan which was 12.2%? I take it the sheet automatically works out the 8£ compound interest rate in the final column.

4) Is there a letter template to try to claim back these unfair charges from Blemain

Any advice would be grateful