FYI - some flightschools themselves offer an excess waiver for a small fee....ask your local SFH school - its also a nice tie in to them if you do this.
My flight school charge something like (but I could get this wrong) - £200pa to "waive" the excess on an R22 - and £400pa to waive the excess on the R44.....
....a nice earner for them if nothing hqppens - but personally if I pranged one and got hit by the excess (thought it was more like £5k for R22 ?) that would ground me in the short term....