yes, usually anything less than a £1 coin can be repaired, however, you can still notice the repair. although only when you really look for it.
i had one repaired that was around £2 sized, however, when i rang autoglass for a quote they said they will try fix it but theres a chance it will crack the windscreen, if it does i have to pay for the cost of fixing it and a new windscreen! i promptly hung up and rang a mate of a mate who said he would repair it if he can for £15 if it cracks he will replace the windscreen for £90 and write off the payment for the repair.
im now onto my 4th windscreen! (In 4 years!) i much like you have a excess with my insurance, however just find it easier to pay the added tenner for him to do it and not go through insurance (especially after a mate claimed for his windscreen then when his years policy was up he found out it counted as a claim and he only got a years ncb that could be used with that same company!)