Get it professionally repaired. The chances of it getting worse are high if you don't. Contact your local caravan shop for details of who does it near you. Worth the money.
buy some canvas and stick a patch on from the inside using impact adhesive (available from any DIY store). its little known fact but this type of adhesive is suitable for canvas (states so on tin in small print) and i can vouch for it as i have renovated a 1978 combi camp and replaced a patch of the canvas approx 1m x half metre in size as well as numerous smaller patches, been tried and tested in lovely easter weather, mid wales this years (no leaks). its not the prettiest way to repair but will certainly work as well as any professional repair and will cost the price of the glue plus canvas (less than £10 quid). would also be wise to re-proof it on the outside also after repair carried out.
Personally i'd probably use tenatious tape on such a small hole, I've used it on my FC and it seems to work well plus not hugely noticable as it is clear. I have also used canvas patches and copydex on an old TT which worked fine but matching the canvas colour was not easy due to fading and so didnt look as good as the tenacious tape.
For me it depends where the hole is and how much stress that area's under.
Professional repair is always best but its expensive, DIY repair can be done with glue and patches but beware the edges of the patch fraying over time and glue doing damage to the fabric and stopping re proofing. A old quick fix for a small hole is to simply sew a suitable badge over the outside of the hole (if its in a suitable place). OR make a patch with a hemmed edge to stop fraying. But remember to put a piece inside the canvas too so you sandwich the hole between the badge and the inner patch. If DIY ing it you'll need a sailmakers palm, canvas needle and suitable thread. Its extremely difficult to do it without these items becasue of the weight of the canvas. I notice you live in Taunton, there are some decent marine chandlers & sailmakers in that part of the world. They may be able to help or advise or even repair if for you if there's no tent or awning specialists near.
WWW.tentvaletingservices.com of Bolton should be able to supply you with canvas patches colour matched to your fiesta and the materials to stitch it if you wanted to have a go yourselves.
------------- Aye the force is strong in ye but thoo's not yet a Geordie.
This is what tent valet services advised me to do with two small nicks that I had in my canvas:
Get some "Seam Grip"
http://cgi.ebay.co.uk/Seam-Sealant-Seam-Grip-Waterproofs-Seals-MCNETT_W0QQitemZ380125018925QQcmdZViewItemQQptZUK_SportingGoods_Wetsuits_WatersportsClothing_CA?hash=item5881377b2d&_trksid=p3286.c0.m14&_trkparms=65%3A12|66%3A2|39%3A1|72%3A1683|240%3A1318|301%3A1|293%3A1|294%3A50
Put some masking tape on the back of the hole, MUST be masking tape, no other type.
Put a blob of seam grip on the other side of the hole and let it cure and dry for 12 hours.
Once it's completely dry remove the masking tape.
This works, totally water proof but just leaves you with a dark small patch on the canvas where the glue is.
Al
I have a tiny hole in my awning side, were something was rubbing, I rang isabella asked them wot i can do, They sent me a iron on patch. so i use sirrated sissors so theres no stright edges,then iron the patch on. a tenner for a large patch, and the right colour.
------------- Roughing it in style at Calloose caravan and camping holiday park nr St Ives.(seasonal pitch)
Its not a hangover, its wine flu!