Thanks for the response folks, for clarification here are some further details:
Yes, I certainly am a new/naive investor and this is the only investment I have.
I typo'd in my original post - I meant 0.82% OCF, not OCR and hence this is my measure of the charges incl. fund and platform fee.
I have a UK 100 Index (R) fund directly from L&G inside a S&S ISA wrapper.
I opened this is 2011 on the advice of a Motley fool book. I think it may have been "The Motley Fool UK Investment Workbook" but I don't have it anymore so I can't check. It's possible the guidance pointed towards a 'UK Index' rather than a 'UK 100 Index' but again I can't check. I was feeling rather brazen anyway so I was willing to take a punt on the UK 100. Whether good or not, that's how it happened.
Yes, it appears the value has increased most over the past year Brexit etc. I have struggled to find a calculator that will let me compare the same monthly investment on different funds, eg. the value of my investment had I put it into a different fund initially. Does this exist?
From my calculation my investment is now worth the equivalent of putting it in a regular savings account at around 8% APR. Should I be happy with this?
I guess the next logical question is what would it be worth had I chosen a different fund, or indeed the same fund on a cheaper platform?
Does it really matter now? You can't turn the clock back
I would echo bigadaj's comment about Tim Hales' book and the Monevator website as reasonable places to start learning so you can make better investment choices from now on.
First of all decide what you want to invest in, then look at various platforms and decide which offers your chosen investments and which is best suited to your investing style (drip feeding, lump sums etc).